The United States Public Health Service (USPHS) is a division of the Department of Health and Human Services concerned with public health. It contains eight out of the department's eleven operating divisions. The Assistant Secretary for Health (ASH) oversees the PHS. The Public Health Service Commissioned Corps (PHSCC) is the federal uniformed service of the USPHS, and is one of the eight uniformed services of the United States.

Its origins can be traced to the establishment in 1798 of a system of marine hospitals. In 1870 these were consolidated into the Marine Hospital Service, and shortly afterwards the position of Surgeon General and the PHSCC were established. As the system's scope grew, it was renamed the Public Health Service in 1912. The Public Health Service Act of 1944 consolidated and revised previous laws and is the current legal basis for the PHS. A series of reorganizations in 1966–1973 caused a shift where PHS' divisions were promoted into departmental operating agencies, with PHS itself becoming a layer of hierarchy above them rather than an operating agency in its own right.