The survey also examined the prevalence of health behaviors, knowledge, and beliefs about AIDS; medical costs associated with heavy alcohol use and heavy smoking; effects of Operations Desert Shield and Desert Storm on substance use; and pathological gambling in the military. The survey sample included approximately 25,000 military personnel selected from 63 geographic locations worldwide, and usable questionnaires were received from 16,395 military personnel, for a response rate of 77.3 percent. Overall survey findings indicate the military has made steady and notable progress over the past 12 years in combating illicit drug use and smoking and in reducing drug and alcohol problems but has made less progress in reducing heavy drinking. Despite notable progress, cigarette smoking remains common and affects about one-third of military personnel. In addition, the rate of heavy drinking, at a consumption level most likely to result in alcohol-related problems, affects about 15 percent of active duty military personnel. Detailed data are provided on alcohol, drug, and tobacco use; negative effects of alcohol and drug use; and medical costs of alcohol and cigarette use. Military programs to combat alcohol, drug, and tobacco use are discussed, as well as the importance of improving knowledge about AIDS. Supplemental tables are appended. 20 references, 6 tables, and 40 figures