At its eighteenth session, held on 9 July 1998 at the headquarters of the Food and Agriculture Organization of the United Nations (FAQ), in Rome, the Ecosystem Conservation Group (ECG) decided that the issue of biological diversity and the urban environment was a priority topic for the Group's members and that an issue paper should be prepared on the topic by FAO and the United Nations Educational, Scientifc and Cultural Organization (UNESCO). In particular, the paper should identify key issues in the interfaceof biological diversity and the urban environment and assist ECG members to promote interlinkages, complementarity and compatibility of their relevant work programmes. Following substantive discussiors within ECG of the subject matter, and based on comments by ECG members on an earlier version of the paper, the present paper has been prepared by UNESCO, working in collaboration with FAO.