Small Group Education (SGE) to promote breast cancer screening was implemented in a community-wide program. Based on diffusion of innovations theory, SGE initially was directed toward women at higher occupation and education levels and then progressively shifted toward more vulnerable populations of women at risk of not getting screening. During the four-year intervention, 116 volunteers led SGE presentations, with 8,184 women participating in 740 groups at work sites, organizations, residences, and churches. High participation in SGE and positive participant responses suggest that delivery of SGE using a social diffusion model was an effective method for reaching women throughout the community.