It was developed from 1955 US Army trials from the Bell Model 204, the intial designation of HU-1 (helicopter utility) led to its nickname. It was first used by the military in 1959 and went into triservice production in 1962 as the UH-1. The last were produced in 1976 with more than 10,000 made in total, of which the majority (7,000 or so) were deployed in Vietnam. In Vietnam 2,202 Huey pilots were killed and 5,086 helicopters lost.
In Vietnam primary missions included general support, air assault, cargo transport, aeromedical evacuation, search and rescue, and electronic warfare. During the conflict the craft was upgraded, notably to a larger version based on the Model 205 intially designated the UH-1D which flew operationally from 1967.
It was phased out by the introduction of the UH-60 Blackhawk. But the Army UH-1 Residual Fleet means that around 700 Uh-1s were supposed to be retained until 2015. Army support for the craft ends in 2004.