Compared to other adults, those with intellectual and developmental disabilities have more health issues, yet are less likely to receive preventative care. One strategy that has shown success in increasing prevention activities and early detection of illness is the periodic comprehensive health assessment (the health check). Effectively moving evidence into practice is a complex process that often receives inadequate attention. This qualitative study evaluates the implementation of the health check at two primary-care clinics in Ontario, Canada, and the influence of the clinic context on implementation decisions. Each clinic implemented the same core components; however, due to contextual differences, some components were operationalized differently. Adapting to the setting context is important to ensuring successful and sustainable implementation.