We assessed determinants of condom use postulated by the IMB model among STD patients (N = 1474). The model provided acceptable fit to the data (CFI = 0.99, RMSEA = .04). Information was unrelated to condom use but had a negative effect on behavioral skills. Motivation had a positive effect on behavioral skills and condom use. Behavioral skills had a positive effect on condom use. In multiple-groups analyses, stronger associations between motivation and condom use were found among participants reporting no prior STD treatment. Interventions among STD patients should include activities addressing condom use motivation and directly enhancing condom skills.