The relationship between substance use (alcohol, drugs, and tobacco) and health (health practices, number of illnesses, number of physician visits, and days hospitalized) was examined using data from the 1985 Worldwide Survey of Alcohol and Nonmedical Drug Use Among Military Personnel. Substance users, particularly heavy users, were less likely than nonusers to engage in health practices and were more likely to experience illness, physician visits, and hospitalizations. Significant effects on the number of illnesses were observed for heavy drinkers compared with abstainers, drug users other than marijuana only users compared with nonusers, and those who smoked one or more packs of cigarettes per day compared with nonsmokers. The potential of substance use programs in improving health status and health promotion programs in reducing substance use among military personnel is discussed.