Embedding health messages into sermons is a potentially valuable strategy to address HIV and other health disparities in churches that predominantly serve racial and ethnic minorities. This study explores implementation of an HIV sermon as part of a multi-component intervention in three churches (Latino Catholic, Latino Pentecostal, and African American Baptist) in high HIV prevalence areas of Los Angeles County, California. Clergy were given an HIV sermon guide that included local public health data, stigma reduction cues, HIV testing messages, and a sample sermon. Findings are based on a process evaluation (i.e., reach, dose delivered, fidelity, and implementation) and in-depth content analysis to explore HIV frames and messages used by clergy. Sermons were audio-recorded, transcribed verbatim, and coded using an inductive approach. Complementary data were collected through systematic observation. Overall, five clergy delivered nine HIV sermons to majority African American or Latino audiences. On average, 174 congregants were reached per sermon. We found large variation in fidelity to communicating key HIV messages from the sermon guide. While promoting HIV testing from the pulpit seemed viable and acceptable to all the participating clergy, fewer embedded explicit stigma reduction cues. Most spoke about HIV using compassionate and non-judgmental terms, however, issue framing varied across clergy. Structured training of clergy may be necessary to implement the more theoretically driven stigma reduction cues included in the sermon guide. More research is needed on the viability and acceptability of embedding specific health promotion messages into sermons.