Challenge: London reportedly has Ontario’s third-highest HIV infection rate, and a small (2.2%) but growing African, Caribbean and other Black (ACB) population. These diverse communities historically faced racism, exploitation and social exclusion, which have lasting impacts. Although a target population for HIV prevention, they are difficult to reach for research and programming, especially in London and similar urban-rural locales with few ACB-specific resources. In ACB communities, HIV is most commonly spread through heterosexual contact, yet cultural and religious norms often discourage discussions about sex and sexuality, whether normative or non-normative. Homophobia, racism and HIV-related stigma discourage ACB persons from seeking information about HIV/AIDS. Additionally, few local researchers have worked with ACB communities; service providers are seldom researchers; trust is lacking between ACB communities and service providers; and there are inter- and intra-ethnic separations in ACB communities. Approach: The Black, African and Caribbean Canadian Health Study is an interdisciplinary, mixed-methods, community-based epidemiologic project about health and HIV in London’s ACB communities. This project involved: networking with ACB community members, service providers, and academic researchers; learning about ACB communities through semi-ethnographic work; immersing a multi-disciplinary team in health research; and interviewing community members and service providers. Team members represent AIDS service organizations, a settlement agency serving ethno-racial minority communities, and a university. ACB persons comprise over half of the research team. Discussion: Community-based research is unusual in epidemiology but necessary for conducting good-quality epidemiologic studies in communities like London’s ACB communities. It helps build capacities of service providers, community members and academic researchers to undertake research. Taking our approach, we identified: relevant epidemiologic survey topics; methods for recruiting respondents; and appropriate question formats. The team was able to: build relationships with community members and service providers; promote the project; identify individuals to help recruit respondents; and learn about norms in different communities.