This paper presents lessons learned from an intervention designed to provide HIV prevention counseling within a hospital-based, multidisciplinary HIV clinic. The model, Positive Prevention, used Master's-level social workers (MSWs) as intervention specialists to minimize burden on primary care providers and to offer a replicable way to provide prevention in a similar setting. The intervention goal was to reduce risk behaviors through Motivational Interviewing, a patient-centered counseling approach with proven success impacting behavioral change. Implementation experiences offer insight into the challenges of using MSWs as prevention specialists. Particular challenges were related to patient engagement and retention. Experiences early in the implementation process were informative and allowed for adaptations to facilitate a more viable program; however even after executing new strategies, many of the program issues remained. Thus, the Positive Prevention model is not recommended as a best HIV prevention model for replication in similar high-volume, hospital-based, multidisciplinary HIV clinic settings.