Medicare's August 2026 file counts US doctors in 30 specialties, from 46,004 emergency physicians and 29,847 cardiologists to 3,608 allergists

Findings

1. Medicare's Doctors and Clinicians file dated 18 August 2026 lists 1,627,468 clinicians, 703,381 of them with an MD or DO credential, and 487,391 whose primary specialty is one of the 30 specialties counted here.
2. Of the 30 specialties, emergency medicine is the largest, with 46,004 clinicians, ahead of anesthesiology (45,261), radiology (38,040), obstetrics and gynecology (34,514) and cardiology (29,847), and allergy and immunology is the smallest, with 3,608.
3. Women are a majority in five specialties, led by OB/GYNs (69.8%) and pediatricians (60.4%), and 9.4% of orthopedic surgeons are women.
4. Among clinicians with an MD or DO credential, DOs are 22.7% of physiatrists and 22.0% of emergency physicians, against 1.7% of radiation oncologists.
5. Medicare claims show telehealth for 66.9% of endocrinologists and 60.2% of rheumatologists, and for under 5% of anesthesiologists, ophthalmologists, podiatrists, emergency physicians, radiologists and pediatricians.
6. 81.3% of oncologists practice in a group of 100 or more clinicians, against 38.7% of dermatologists, 31.8% of ophthalmologists and 28.7% of podiatrists.
7. Emergency physicians have the most recent median graduation year (2012, with 40.8% graduating in 2015 or later), and cardiothoracic surgeons the earliest (1998, with 28.2% graduating before 1990).
8. California has the most clinicians in every specialty but one: Florida leads pain management, with 492 of its 4,645 clinicians (10.6%).
9. The file undercounts specialties whose patients rarely use Medicare. It lists 13,093 pediatricians, fewer than dermatologists, and 72.8% of them accept Medicare assignment, against 89.5% to 97.0% in every other specialty.

How to read these numbers. A clinician is one National Provider Identifier (NPI). A clinician counts in a specialty when at least one of their Medicare enrollments lists one of its CMS primary specialty codes, so each count answers "how many clinicians in the file practice this specialty as their primary one". The file covers clinicians enrolled in Medicare and draws on the last 12 months of Medicare claims, so clinicians who do not bill Medicare are mostly missing. Subspecialists who list a broader primary specialty, such as a cardiologist enrolled under internal medicine, count under that broader specialty. 1,032 clinicians appear in more than one of the 30 specialties (1,027 in two and 5 in three), so the 30 counts add up to 488,428 for 487,391 people.

How many clinicians practice in each specialty

Emergency physicians46,004

Anesthesiologists45,261

Radiologists38,040

OB/GYNs34,514

Cardiologists29,847

Psychiatrists28,726

Orthopedic surgeons25,173

General surgeons23,622

Neurologists18,775

Ophthalmologists18,380

Oncologists17,153

Podiatrists16,132

Gastroenterologists16,018

Dermatologists13,599

Pediatricians13,093

Pulmonologists11,733

Urologists10,341

Nephrologists10,124

Otolaryngologists (ENT)9,995

Physiatrists (PM&R)9,360

Infectious disease physicians7,281

Endocrinologists7,254

Neurosurgeons5,761

Rheumatologists5,538

Radiation oncologists5,386

Plastic surgeons4,737

Pain management physicians4,645

Vascular surgeons4,200

Cardiothoracic surgeons4,128

Allergists3,608

Source: Carroway Research count of the CMS Doctors and Clinicians National Downloadable File, dated 18 August 2026. One clinician is one NPI. The CMS codes behind each specialty are in clinicians-by-specialty.csv.

The five largest of the 30 specialties are emergency medicine (46,004), anesthesiology (45,261), radiology (38,040), obstetrics and gynecology (34,514) and cardiology (29,847). Dermatology counts 13,599 clinicians, gastroenterology 16,018, neurology 18,775 and urology 10,341. The smallest are cardiothoracic surgery (4,128) and allergy and immunology (3,608).

Some specialties join several CMS codes. Cardiology is general cardiology (21,412 clinicians), interventional cardiology (5,200), cardiac electrophysiology (2,795) and advanced heart failure and transplant cardiology (974), and a clinician listed under two of them counts once. Radiology is diagnostic (35,448) and interventional (3,231). Oncology is hematology and oncology (10,423), medical oncology (4,347), surgical oncology (1,436) and gynecologic oncology (1,174). Radiation oncology (5,386) is counted on its own. A few subspecialty codes sit outside the specialty a reader might expect: 518 clinicians list micrographic dermatologic surgery (Mohs surgery) as their primary specialty and are not among the 13,599 dermatologists, and 289 epileptologists are not among the neurologists (subspecialties-outside.csv). The counts for all 99 primary specialties in the file, one row each, are in all-primary-specialties.csv.

California has the most clinicians in every specialty except pain management, where Florida leads with 492 of 4,645 (10.6%). Counts for every state and territory are in clinicians-by-state.csv.

Table 1. Clinicians and their profile by primary specialty, CMS Doctors and Clinicians file dated 18 August 2026.

Women and telehealth are shares of all clinicians in the specialty. The DO share is of clinicians with an MD or DO credential. The last column is the share whose largest group practice has 100 or more clinicians. Counts behind every share are in specialty-profile.csv.

Primary care, nurse practitioners and physician assistants

The largest primary specialty in the file is nurse practitioner, with 284,684 clinicians, followed by physician assistants (138,850). Internal medicine (105,887) and family practice (98,041) are the largest physician specialties, and 24,166 clinicians list hospitalist as their primary specialty. These groups sit outside the 30 specialties, as do other large physician specialties such as pathology (13,140) and critical care (6,206), and the same counting rules apply.

Who works in each specialty

OB/GYNs69.8%

Pediatricians60.4%

Endocrinologists59.3%

Dermatologists54.7%

Rheumatologists52.5%

Allergists46.6%

Infectious disease physicians45.3%

Psychiatrists43.1%

Oncologists40.5%

Neurologists38.6%

Physiatrists (PM&R)34.1%

Emergency physicians33.2%

Nephrologists31.6%

Ophthalmologists30.8%

Podiatrists30.1%

General surgeons29.9%

Anesthesiologists28.9%

Radiation oncologists27.8%

Pulmonologists26.5%

Radiologists24.8%

Gastroenterologists24.8%

Plastic surgeons23.7%

Otolaryngologists (ENT)23.2%

Vascular surgeons20.2%

Cardiologists17.2%

Pain management physicians15.8%

Urologists15.4%

Cardiothoracic surgeons11.9%

Neurosurgeons10.9%

Orthopedic surgeons9.4%

Source: Carroway Research, CMS Doctors and Clinicians file, dated 18 August 2026. Gender as recorded by CMS. Clinicians and women per specialty are in specialty-profile.csv.

Women make up 69.8% of OB/GYNs, 60.4% of pediatricians, 59.3% of endocrinologists, 54.7% of dermatologists and 52.5% of rheumatologists. Four surgical specialties sit at the other end: orthopedic surgery (9.4%), neurosurgery (10.9%), cardiothoracic surgery (11.9%) and urology (15.4%), followed by pain management (15.8%) and cardiology (17.2%).

The AAMC's count of active physicians in 2024 puts women at 66.7% of pediatricians, 64.1% of OB/GYNs and 6.8% of orthopedic surgeons (AAMC 2025 key findings). The two sources count different populations, two years apart. Leaving out hand surgery, 8.9% of the file's 23,369 orthopedic surgeons are women, against 17.0% of the 1,804 clinicians with a hand surgery line.

Osteopathic physicians (DOs) are most common in physiatry (22.7% of 8,848 MDs and DOs) and emergency medicine (22.0% of 44,147), and least common in radiation oncology (1.7%), cardiothoracic surgery (2.8%) and plastic surgery (2.9%). Podiatrists hold a DPM, so the DO share does not apply to them.

By graduation year, emergency medicine is the most recent specialty, with a median of 2012 and 40.8% of its clinicians graduating in 2015 or later. Pediatrics follows with a median of 2009. Cardiothoracic surgery has the earliest median, 1998, and 28.2% of its clinicians graduated before 1990, as did 26.8% of allergists and 26.5% of cardiologists.

Telehealth and practice size

Oncologists81.3%

Cardiothoracic surgeons80.0%

Pulmonologists75.9%

Neurologists75.1%

Radiologists75.0%

Anesthesiologists74.8%

Cardiologists74.3%

Neurosurgeons74.3%

Infectious disease physicians73.7%

Endocrinologists73.7%

Gastroenterologists71.2%

Radiation oncologists70.4%

Vascular surgeons70.1%

General surgeons69.6%

Orthopedic surgeons67.4%

Urologists67.1%

OB/GYNs66.0%

Emergency physicians64.9%

Rheumatologists64.8%

Otolaryngologists (ENT)61.2%

Pediatricians56.9%

Physiatrists (PM&R)53.9%

Psychiatrists51.9%

Nephrologists50.8%

Plastic surgeons49.3%

Pain management physicians44.4%

Allergists42.4%

Dermatologists38.7%

Ophthalmologists31.8%

Podiatrists28.7%

Source: Carroway Research, CMS Doctors and Clinicians file, dated 18 August 2026. Group size is CMS's count of clinicians in the group practice. Shares with no group practice are in specialty-profile.csv.

In oncology (81.3%), cardiothoracic surgery (80.0%), pulmonology (75.9%), neurology (75.1%) and radiology (75.0%), most clinicians work in a group of 100 or more. In podiatry (28.7%), ophthalmology (31.8%), dermatology (38.7%) and allergy (42.4%), most do not. Pediatricians are the most likely to have no group practice on file at all (30.2%), followed by podiatrists (26.5%) and plastic surgeons (25.6%).

Medicare claims show telehealth for 66.9% of endocrinologists, 60.2% of rheumatologists, 57.9% of oncologists, 52.2% of neurologists and 49.0% of psychiatrists. The lowest shares are in anesthesiology (2.8%), ophthalmology (2.8%), podiatry (2.9%), emergency medicine (3.0%) and radiology (3.4%).

Radiologists are the most likely to practice at more than one location (71.1%), then cardiologists (54.0%) and orthopedic surgeons (51.0%). Dermatologists are the least likely (31.5%).

What the file counts and misses

The file lists clinicians enrolled in Medicare, a narrower group than all practicing physicians. The AAMC counted 1,032,365 active physicians in the US in 2024, 866,460 of them in direct patient care. The Medicare file lists 703,381 clinicians with an MD or DO credential, and 322,733 more with no credential recorded, some of them physicians.

Pediatrics shows the gap most clearly. The AAMC names internal medicine, family medicine and pediatrics as the three largest specialties among active physicians in 2024. In the Medicare file, pediatrics is the primary specialty of 13,093 clinicians, fewer than dermatology's 13,599, since Medicare covers few children. Only 72.8% of those pediatricians accept Medicare assignment, the lowest share of the 30 specialties. Any specialty falls short in the same way wherever some of its clinicians do not bill Medicare.

Method

Source. The CMS Doctors and Clinicians National Downloadable File, dated 18 August 2026 and published 10 September 2026 (Provider Data Catalog dataset mj5m-pzi6), the current release on 29 September 2026. The next release is due on 15 October 2026. The 30 specialties are the specialty files Doctor Email List builds from each release, and the counts match its files one for one.

What the file holds. CMS publishes one line per clinician, enrollment, group and address, drawn from Medicare enrollment records (PECOS) and the last 12 months of Medicare claims. The release has 3,388,628 lines for 1,627,468 clinicians. The primary specialty is the one the clinician reported in each enrollment, and 9,519 clinicians list different primary specialties in different enrollments.

Counting. A clinician is one NPI. Each of the 30 specialties is the set of CMS primary specialty codes listed in clinicians-by-specialty.csv, and a clinician counts in a specialty when any of their lines carries one of those codes. A clinician counts once within a specialty and can count in more than one. Primary care and nurse practitioner groups in other-groups.csv use the same rule. Some subspecialty codes are not part of the specialty a reader might expect: micrographic dermatologic surgery, or Mohs surgery (518 clinicians outside dermatology), epileptologists (289 outside neurology), cell therapy and transplantation (161 outside oncology) and adult congenital heart disease (77 outside cardiology), with the counts in subspecialties-outside.csv.

Profile measures. Each clinician's gender, credential, graduation year, telehealth flag, Medicare assignment, group size and state come from one line per clinician in the specialty: the line with the largest group, then the lowest address ID, then the newest enrollment. In this release, gender and graduation year never differ between a clinician's lines, and the telehealth flag differs for 1 clinician, credential for 8 and assignment for 3.

• Women: the gender field is F. It reads M, F or U.
• DO share: DOs as a share of clinicians whose credential is MD or DO. Not reported for podiatrists, who hold a DPM.
• Graduation year: the year the clinician graduated from medical school, or podiatry school for podiatrists.
• Telehealth: CMS flags a clinician when Medicare fee-for-service claims show telehealth services over video or audio.
• Group of 100 or more: the largest group practice the clinician is linked to has 100 or more members, by CMS's count of the clinicians in that group. No group means none of the clinician's lines links to a group practice.
• More than one location: two or more distinct practice addresses. CMS gives offices in one building the same address ID apart from its last 2 characters, so offices in one building count as one location.
• Medicare assignment: the clinician accepts the Medicare-approved amount as payment in full. The other value is "may accept".

Exclusions. 7 lines with a blank or numeric primary specialty are left out of the specialty counts. The 11,780 lines outside the 50 states and DC stay in every count: 10,225 in Puerto Rico and the rest in Guam, the US Virgin Islands and other territories.

Data

The eight CSV files below hold every count and share in this note. clinicians-by-specialty.csv has the count for each of the 30 specialties and the CMS codes behind it. specialty-profile.csv has each specialty's shares with the counts behind them. other-groups.csv covers primary care, nurse practitioners, physician assistants and other large groups, and all-primary-specialties.csv counts every primary specialty in the file. subspecialties-outside.csv counts the subspecialty codes that sit outside a related specialty. clinicians-by-state.csv counts each specialty's clinicians in every state and territory, benchmark-aamc.csv has the AAMC figures quoted above, and coverage.csv traces the counts from the file's lines to the clinicians analyzed. count_specialties.py rebuilds all eight from the public CMS file. They are free to reuse with credit to Carroway Research.

• Clinicians in each of 30 specialties CSV, 30 rows, 1.7 KBOne row per specialty: clinicians (distinct NPIs), lines in the CMS file, and the CMS primary specialty codes that make up the specialty.
• Profile of each specialty CSV, 30 rows, 3.7 KBOne row per specialty: clinicians; women as a count and share; MD, DO, MD or DO and other or blank credentials with the DO share of MDs and DOs; graduation year median, quartiles and the shares graduating in 2015 or later and before 1990; and the shares with telehealth, more than one practice location, a group of 100 or more clinicians, no group practice and Medicare assignment.
• Primary care, nurse practitioners, physician assistants and other large groups CSV, 10 rows, 0.6 KBOne row per group outside the 30 specialties: clinicians, women share, telehealth share and the CMS primary specialty codes counted.
• Every primary specialty in the file CSV, 99 rows, 3.2 KBOne row per CMS primary specialty: clinicians (distinct NPIs) and lines in the file.
• Subspecialty codes counted outside a related specialty CSV, 4 rows, 0.3 KBFour CMS subspecialty codes (micrographic dermatologic surgery, epileptologists, adult congenital heart disease, cell therapy and transplantation): clinicians with the code and how many of them are not counted in the related specialty.
• Clinicians in each specialty by state CSV, 1,629 rows, 48.3 KBOne row per specialty and state or territory: clinicians, the state's share of the specialty and its rank within the specialty.
• AAMC figures for 2024 next to the Medicare file CSV, 9 rows, 1.1 KBActive and direct patient care physicians and the women's share in three specialties from the AAMC's 2025 key findings, next to the closest measure in the Medicare file (including orthopedic surgeons with and without hand surgery), with the source link.
• Coverage and consistency CSV, 19 rows, 1.4 KBLines and clinicians in the file, credentials, clinicians counted in two or three specialties, lines outside the 50 states and DC, and the clinicians whose lines disagree on each profile field.