Widespread type II diabetes among North American Indians and certain other populations is a relatively recent medical phenomenon. Increased prevalence of diabetes appears to be related to sudden cultural shifts toward sedentary lifestyle and increased caloric intake. These changes, super-imposed on a genetic predisposition to diabetes, pose a community health threat to the Zuni and similar populations. Regular aerobic exercise is clearly beneficial to most type II diabetics. The key public health issue is how to establish community participation in effective aerobic activity. The Zuni Diabetes Project, fully described here, serves as a model in this respect.