A gold color metal and enamel device 1 1/8 inches (2.86 cm) in height overall consisting of a white Greek cross with a Korean Taeguk at its center and one within each upper angle of the cross, and radiant from the lower angles three gold rays, all within a maroon annulet with two gold billets each bearing a green ermine spot and each surmounting the annulet at the ends of the lateral arms of the cross between the inscriptions "OUR MISSION" on the upper portion of the annulet and "YOUR HEALTH" on the lower, all in gold letters.
Maroon and white are the colors used for the Army Medical Department and a cross is symbolic of aid and assistance. An ermine spot is associated with Europe and the two refer to the unit's participation in the Rhineland and Central Europe campaigns, World War II. The three Taeguks and six rays represent the unit's nine campaigns in the Korean War: the two Taeguks above the cross denote the two Meritorious Unit Commendation Streamers, and the one on the cross with the colors red and blue combined with white and green refers to the Republic of Korea Presidential Unit Citation. The billets allude to protection and support. The annulet represents strength and determination.
The distinctive unit insignia was originally approved for the 121st Evacuation Hospital on 19 January 1972. It was redesignated effective 16 April 1994, for the 121st General Hospital with description and symbolism revised. The insignia was redesignated effective 16 October 2006, for the 121st Combat Support Hospital.