Three single-session preventive interventions for reducing sexually transmitted disease (STD) and human immunodeficiency virus infection risk behaviors were evaluated with a sample of 400 men who attended a large military STD clinic. A quasi-experimental, pre-evaluation/postevaluation design was used, comparing standard clinic care alone versus standard care combined with 1 of 3 experimental interventions: health-risk appraisal, interactive video, and targeted situational behaviors. Questionnaire data were collected at baseline and during follow-up visits at 2 weeks and 2 months. Findings indicated that the health-risk appraisal and interactive video increased adherence with clinic recommendations to abstain from sex (chi(2)3199=19.67; P<.001) and increased readiness to change "risky" partner-selection behavior (chi(2)2194=6.42; P<.04). Follow-up data suggested that STD-related risk behavior was particularly resistant to change but that the single-session intervention had some impact, which could be viewed as a "priming" effect that enhances multisession interventions.