This report contains an update through June 2017 of the results of routine screening for antibodies to the human immunodeficiency virus among civilian applicants for military service and among members of the active and reserve components of the U.S. Armed Forces. During the surveillance period, annual seroprevalences among civilian applicants for military service peaked in 2015 (0.33 per 1,000 tested) and then decreased slightly in 2016. Seroprevalences among Marine Corps reservists, Navy active component service members, and Navy reservists also peaked in 2015. Overall (1 January 2012 through 30 June 2017) seroprevalences were highest for Army reservists, Army National Guard members, Navy reservists, and Navy active component members. Among active and reserve component service members, seroprevalences continue to be higher among males than females.