This article describes a mixed-methods needs assessment, or developmental evaluation, that was conducted for the providers and stakeholders of Oklahoma's community-based organizations (CBOs). The needs assessment, which was the first phase in developing training on outcome monitoring for their HIV prevention programs, relied on three evaluation approaches: Behavioral-objectives, participatory, and empowerment. This article describes the background for the needs assessment, the needs assessment process, and the lessons learned. When dealing with such a complex issue as HIV prevention where multiple goals must be achieved for success, a mixed-methods approach to needs assessment may better capture real-world needs. Furthermore, it may increase acceptance of the needs assessment findings and conclusions by the diverse groups that have a stake in the evaluation. However, as this study exemplified, implementing and reporting a mixed-methods needs assessment that is based on differing evaluation approaches is complex, challenging, and resource intensive. This study can contribute to theory building for mixed-methods evaluation. (Contains 4 figures and 1 table.)