Retired Army Maj. Jan. P. Gardiner, 37, a decorated combat veteran of the Vietnam conflict, died of cancer Friday at Walter Reed Army Hospital.

An armored officer, Maj. Gardiner served two tours of duty in Vietnam, first in the mid-1960s and again in the early 1970s. His decorations included three Bronze Star medals, three Air Medals, and the Purple Heart.

During his 14-year Army career, he qualified as a tank unit commander and parachutist. He had served as an operations officer.

In addition to his tours in Vietnam, he was executive officer of a tank squadron in Germany and staff officer in a number of posts in this country.

Maj. Gardiner was a native of Baltimore. He received his Army commission after graduating from Georgetown University in 1964. He earned a master's degree in personnel management at George Washington University in 1971. He also was a graduate of the command and General Staff School in Fort Leavenworth.

Since retiring from the Army for reasons of health in 1978, Maj. Gardiner had been a realtor with Sampson Realty in Burke, Va. He was a resident of Burke.

Survivors include his wife, Diane Gill Gardiner, and three sons, Jarrett, Jason, and Jonathan, all of Burke, and his mother, Ellen Martin Gardiner, and a brother, Joseph, both of Baltimore.

The family suggests that expressions of sympathy be in the form of contributions to the American Cancer Society.