Critical care fellowship training in the United States differs based on specific specialty and includes medicine, surgery, anesthesiology, pediatrics, emergency medicine, and neurocritical care training pathways. We provide an update regarding the number and growth of US critical care fellowship training programs, on-duty residents and certified diplomates, and review the different critical care physician training pathways available to residents interested in pursuing a fellowship in critical care. Data were obtained from the Accreditation Council for Graduate Medical Education and specialty boards (American Board of Internal Medicine, American Board of Surgery, American Board of Anesthesiology, American Board of Pediatrics American Board of Emergency Medicine) and the United Council for Neurologic Subspecialties for the last 16 years (2001-2017). The number of critical care fellowship training programs has increased 22.6%, with a 49.4% increase in the number of on-duty residents annually, over the last 16 years. This is in contrast to the period of 1995 to 2000 when the number of physicians enrolled in critical care fellowship programs had decreased or remained unchanged. Although more than 80% of intensivists in the US train in internal medicine critical care Accreditation Council for Graduate Medical Education-approved fellowships, there has been a significant increase in the number of residents from surgery, anesthesiology, pediatrics, emergency medicine, and other specialties who complete specialty fellowship training and certification in critical care. Matriculation in neurocritical care fellowships is rapidly rising with 60 programs and over 1,200 neurocritical care diplomates. Critical care is now an increasingly popular fellowship in all specialties. This rapid growth of all critical care specialties highlights the magnitude of the heterogeneity that will exist between intensivists in the future.
