The purpose of this study was to evaluate the acceptability and the comparative efficacy of brief HIV risk reduction interventions to increase condom use during paid anal sex by street-based male sex workers (MSWs). Of the 399 street-based MSWs who participated in the evaluation of acceptability, 112 participated in the evaluation of efficacy. Acceptability was evaluated by assessing completion rates. Intervention efficacy was assessed across two brief interventions, a "standard" and a "standard-plus" interventions. The primary outcome of concern was condom use during paid anal sexual encounters. In addition to this variable, changes in drug use, needle use, condom use beliefs, and condom use intention were also assessed. Results showed that almost two thirds of MSWs enrolled in a brief intervention completed it. Completion rates varied by age, race/ethnicity, sexual orientation, and HIV status. Condom use during paid anal sex increased postintervention. In addition, condom use intentions, positive condom use outcome expectations, and condom use normative expectations increased preintervention to postintervention. However, there were no significant differences between the standard and the standard-plus brief interventions in any of the outcomes measured. Brief interventions to reduce the HIV risks are acceptable to MSWs and are efficacious for reducing unprotected anal sex during paid sexual encounters.