This page compares two distinct NUCC-taxonomy specialties tracked by the CMS National Plan and Provider Enumeration System: Emergency Medicine Physician, which currently counts 64,463 enrolled providers across 56 U.S. states and territories, and Undersea and Hyperbaric Medicine (Emergency Medicine) Physician, with 202 providers across 43 states. Each clinician on these rosters selected a primary NUCC code at NPI enrollment, so the totals measure how many providers self-identify their primary practice as Emergency Medicine Physician or Undersea and Hyperbaric Medicine (Emergency Medicine) Physician rather than the total population ever trained or credentialed in either field — dual-certified clinicians show up under whichever code they registered first.

On national volume, Emergency Medicine Physician carries the larger provider roster (64,463 vs 202), and Emergency Medicine Physician has the wider geographic footprint at 56 states versus 43. The top Emergency Medicine Physician concentration sits in California (6,965 providers), while Undersea and Hyperbaric Medicine (Emergency Medicine) Physician peaks in Texas (34). The per-capita columns in the table below normalize each state's raw count against 2023 Census population estimates, which matters because absolute provider counts track population scale first and specialty density second — a small state with a strong training pipeline can out-rank a larger state on per-100K availability.

Use this comparison to understand relative availability, not to judge clinical substitutability — Emergency Medicine Physician and Undersea and Hyperbaric Medicine (Emergency Medicine) Physician are distinct specialties with different scopes of practice, training requirements, and conditions they treat, even when their NUCC categories overlap. Important: PlainDoctor is a directory of publicly available CMS government data, not medical advice, a provider rating, or a recommendation about which specialty a patient should consult. Always work with a licensed clinician to determine which specialty is appropriate for your condition, verify any specific provider through the NPPES NPI Registry and the relevant state medical board, and consult the NUCC taxonomy documentation for the formal scope-of-practice definitions behind each specialty code.