Human immunodeficiency virus (HIV) and sexually transmitted disease (STD)-related risks in peacekeeping troops is a concern when they are stationed in areas of high HIV prevalence. We carried out an assessment of a situationally focused individual HIV/STD reduction intervention (where avoidance of risk situations, as well as risk behaviors, are emphasized) in one Nigerian military unit (N = 1,222), with a comparable unit from the same service as a waiting list control (N = 987). The intervention consisted of a possible five modules that were presented to groups of up to 50 personnel. Data were collected on reported sexual behaviors, condom beliefs, sexual risk behaviors with casual partners, and number of interventions attended. Data indicated significant increases in reported condom use with casual partners and positive condom beliefs at 6- and 12-month follow-up. Risk behavior was reduced 30% from baseline at 6 months and 23% from baseline at 12 months. There was also a significant dose-response effect for number of interventions attended. These data suggest that relatively brief situationally focused individual interventions are effective in military and West African contexts in reducing HIV/STD risk behaviors.