Let us build cities for life: the national campaign of Local Agenda 21s in Peru describes the establishment of a national forum to promote the development and implementation of Agenda 21 in cities in Peru which, today, brings together representatives from 41 institutions in 18 cities. The paper describes the origin, development, vision, strategies and work to date of the forum, showing how it developed from a conventional project which depended on the technical assistance and initiatives of a local NGO into a network of many different actors from many urban centres in Peru who, together, form an autonomous and independent entity. The paper outlines the main environmental problems in Peru's urban areas and the unsupportive national framework within which urban authorities and other urban actors strive to address environmental problems.