A gold color metal and enamel insignia 1 3/16 inches (3.02cm) in height consisting of a maroon disc within an encircling band divided horizontally at the center, the upper half blue and the lower half composed of thirteen evenly spaced vertical segments of red and white, issuing from the upper edge of the band a gold demi-sunflower; overall an upright sword interlaced with two arrows saltirewise points downs, all gold, the sword entwined with a green serpent and the pommel extending slightly beyond the lower edge of the band, surmounting the sword and arrows at the center a representation of the front view of a white tent.
The blue, red and white design of the encircling band is taken from the first ribbon of the Medal of Honor; it indicates that Irwin General Hospital, a major subordinate element of the U.S. Army Medical Department Activity. Fort Riley is named for General Irwin, known as the "Fighting Doctor" whose gallantry in action in February 1861 was the first deed for which the Medal was awarded. The sword interlaced with the crossed arrows commemorates that action during which General Irwin took command of a unit to rescue a detail surrounded by an Apache war party. The serpent and the sword stand for the Medical Activity; they simulate the Staff of Aesculapius, father of Medicine. The sunflower refers to the sun source of light and healing. In addition, as the state flower of Kansas, it alludes to the Activity's location at Fort Riley. The tent stands for the first Tent Field Hospital which was designed by General Irwin at the battle of Shiloh, Tennessee during the Civil War. The design of that Hospital has since served as a model for modern armies. The colors maroon and white are used for organizations of the Army Medical Department. Green, which was formerly combined with yellow for the guidons of Army Medical units, is a symbol of life, growth and health.
The distinctive unit insignia was originally approved for the Irwin Army Hospital on 16 Jun 1970. It was redesignated for the U.S. Army Medical Department Activity, Fort Riley on 25 Sep 1973.