This article describes agreements gay male couples make about sex outside the relationship and how the process of making those agreements, and their perceived quality, varies depending on couple serostatus. Data include 191 couples recruited in the San Francisco Bay Area from June to December 2004. Monogamous agreements were reported by 56% of participants in concordant-negative, 47% in concordant-positive, and 36% in discordant relationships. The remaining participants reported agreements allowing sex with outside partners in some form. Agreement quality was lowest among men in discordant relationships. Overall, few (30%) reported breaking their agreements; only half of whom reported disclosing those breaks to their partners. Although differences in agreement type, quality, and satisfaction were found among the three couple serostatus groups, rates of breaks and their disclosure did not vary significantly by group. Future HIV prevention efforts aimed at couples must integrate both couple serostatus and relationship-based issues.