Pacific Islanders (PIs) experience high cervical cancer rates in the United States. Stage of diagnosis is also later for PIs than non-Hispanic Whites. The Pap test is severely underutilized among PIs: only 71% of Asian American and Pacific Islander women age 25 years or older received a Pap test within the last 3 years (U.S. average, 82%). Community-based participatory research (CBPR) is increasingly seen as an essential approach in designing and conducting culturally relevant and appropriate studies that reduce cancer incidence and other health disparities among minority and other medically underserved populations. The purpose of this article is to describe the lessons learned thus far regarding the identification, recruitment, and retention of PI community organizations and members into a CBPR-informed, randomized, community trial promoting Pap testing. This 5-year study used CBPR to develop and test the efficacy of a social support intervention for Chamorro, Samoan, and Tongan women to increase Pap testing in southern California. Eligible women were between the ages of 21 and 65, and married or in a long-term relationship with a man for at least 5 years. Women and their husbands or significant others received a 2-hour, culturally tailored workshop that include a group activity, information on Pap testing, a video, and corresponding materials. Comparison participants received a brochure about Pap testing. Three waves of data are collected from all participants: pretest (before workshop or brochure), posttest 1 (immediately after workshop or brochure), and posttest 2 (6 months follow-up). Of the 76 organizations approached to participate in the study, 67 (88.2%) eventually agreed to participate. Thus far, 473 women and 419 men completed the study pretest, post-test, education, and 6-month follow-up. Only 242 women and 204 men of the eligible participants have completed the follow-up survey (63.5% of women and 60.5% of men retained after 6 months). The main strategy to overcome initial recruitment challenges was study staff persistence, because they averaged five contacts with each church or clan leader before receiving confirmation that an educational session can be scheduled. Personal connections provided an introduction to the most appropriate church or clan leader. Other efforts for retention include creation of an online version of the survey, re-attending church services, and creating special events organized around clan activities. Although CBPR improves the cultural competence and relevance of study activities for ethnically diverse populations, selected past research shows that it does not ensure that such designs overcome all of the unique challenges in ethnically diverse communities. PI-specific organizational recruitment and individual retention is influenced by study issues and cultural factors in each community.