Clinical trials have seldom included adequate samples of people of color. Therefore, practitioners serving ethnic minorities often do not have access to readily available evidence-based interventions. This article summarizes the development and empirical evaluation of prevention and treatment manuals designed for low-income ethnic minority populations at San Francisco General Hospital. The manuals were often designed by people of color familiar with the communities for which they were developed. Independent research teams in multi-site national and international clinical trials have evaluated many of these manuals with encouraging results.