A gold color metal and enamel device 1 3/16 inches (3.02 cm) in height consisting of a maroon cross pommé with a gold eight-rayed sun symbol on its center and on each of the four roundels of the cross a disc composed of six wavy bars alternately of white and blue from top to base, and between the upper left and right angles of the cross (in line with and supported by the diagonal rays of the sun symbol), two blue five-pointed stars, their lower two points resting on the cross and their lateral points touching the edges of the discs; supporting and enclosing the cross in base a curving maroon scroll folded twice at either side and inscribed in gold letters with the motto "UT HABEANT VITAM."
White and maroon are the colors used by the Army Medical Department. The cross with heraldic fountains at each end is based on the form attributed in heraldry to St. Michael the Archangel, patron of warriors. The heraldic fountains (discs with six white and blue wavy bars) allude to the name of Springfield (Massachusetts), the original location of the hospital, and symbolize the Four Rivers of Paradise which flow from the Tree of Life, alluding to the life-saving and life-conserving mission of the 309th Combat Support Hospital. The hospital's World War II service in the Leyte and Southern Philippines campaigns is denoted by the two blue stars, while the eight-rayed sun at center, suggested by the Philippine Presidential Seal, is a reference to the Philippine Presidential Unit Citation which the hospital received.
The distinctive unit insignia was originally approved for the 309th Field Hospital on 4 September 1970. It was redesignated effective 21 November 1994, for the 309th Combat Support Hospital with the description and symbolism revised.