Introduction: Data on utilization of ambulatory care and the impact of lifestyle on health among young adults are scarce. Israeli mandatory military service provides a unique opportunity to investigate these topics. Study objective was to analyze the utilization of health care services (HCS) during the first year of military service, and its associations with health behavior at recruitment, in order to plan health services, health classification, and health promotion activities. Methods: We conducted a retrospective cohort study among a representative sample of 5,751 mandatory new recruits between January 1, 2004, and December 31, 2008. Data were collected from the Israeli Defense Force computerized medical and administrative records and from an ongoing health survey among military recruits. Results: During their first year of service, recruits had, on average, more than 7 visits to the primary care clinic, more than 10 dispensed nonchronic medications, and more than 5 days of sick leave. Female sex (OR = 1.27; 1.06-1.51) and current cigarette smoking (OR = 1.57; 1.34-1.84) were significantly associated with increased use of HCS, after controlling for possible confounders. Conclusions: Our findings indicate high utilization of HCS during the first year of military service and highlight the potential effect of cigarette smoking as a risk factor for increased morbidity among apparently healthy young adults. These findings support adding smoking status to fitness assessments and could aid health promotion efforts to reduce smoking rates among adolescents.