Peru's expanding population and rapid urbanization--a result of migration to its largest cities--have stressed the country's public services infrastructure and the provision of public health and environmental health services. In response, the Ministry of Health established the General Directorate of Environmental Health (DIGESA), the branch charged with assuring adequate environmental health services to populations in rural and urban areas. The magnitude of the environmental health problems in peri-urban settlements, however, has exceeded the capacity of DIGESA to respond. The Urban Environmental Health Project is an effort to develop the ability of local communities to address these problems