Methamphetamine is widely used among gay and bisexual men in the West Coast of the United States, and is often used in combination with high-risk sexual activities. This study combined quantitative and qualitative research methodologies to examine sexual risk behaviors among gay and bisexual male methamphetamine abusers as they entered treatment and at 1-year follow-up evaluations. Findings from the quantitative follow-up data demonstrate that gay and bisexual men reduce sexual risk behaviors and sustain those reductions following substance abuse treatment, and qualitative data reveal the meaning of these behavior changes from the perspective of the participant. At 1-year evaluations, associated behaviors of methamphetamine use and sexual risk behaviors were lessened. Although condom use decreased slightly, participants reported fewer anonymous sexual partners, reductions in episodes of both receptive and insertive anal intercourse, and an increased sense of responsibility to disclose their HIV status. This study further demonstrates the value of coupling quantitative with qualitative data in understanding the meanings behind reductions in high-risk behaviors.