This paper argues that normative considerations are more important than attitudinal factors in engaging colorectal cancer screening, and tests a model explaining how unique cultural expressions of social networks influence screening adherence. Structural equation modeling was used to understand colorectal cancer screening in a population-based sample of 341 Japanese Americans aged 50 and over. The model accounted for 25% of the variance in screening adherence. Adherence was most strongly associated with family/friend subjective norms about colorectal cancer screening use. Emotional family support, but not the size of the networks, was indirectly related to adherence via increased family/friend subjective norms, while emotional friend support was directly related to adherence. While usual source of care was directly associated with adherence, better provider-patient communication was directly and indirectly associated with adherence via increased perceived benefits. The findings of this study support strengthening informal support networks to enhance adherence among Japanese Americans at risk.