This paper presents data on substance use by military personnel from a series of worldwide surveys conducted in 1985, 1982, and 1980 with primary emphasis on the 1985 survey. Estimates are based on responses from participants serving on active duty in the Army, Navy, Marine Corps, and Air Force. Results for 1985 indicate pervasive use of alcohol, substantial use of tobacco, and low nonmedical use of drugs among military personnel. Average daily consumption of alcohol declined significantly from 1.4 ounces in 1982 to 1.2 ounces in 1985, but the patterns of use remained relatively constant. Nonmedical drug use during the past 30 days declined significantly, from 27.0% in 1980, to 19.0% in 1982, to 8.9% in 1985. Cigarette smoking declined significantly from 51.4% in 1982 to 46.2% in 1985. Current alcohol and drug use is concentrated among younger, less educated, unmarried, and junior and mid-career enlisted personnel. Cigarette pack years are higher among males, whites, those with less than a high school education, and senior enlisted personnel. Results show progress in reducing drug use and smoking in the military, but little change in patterns of alcohol use. New initiatives and approaches by the military to further reduce substance abuse are discussed.