Mentoring is a powerful tool for development and has been used successfully in the training of school headteachers. It has to be managed wisely however. This article draws on the experiences of a mentoring programme for school principals which has been operating since 1984 in Singapore, and discusses three major issues which impact on success: the selection of mentors; preparation and development; and organisation and operation of schemes. Recommendations in each of these areas are made for those who have the responsibility of implementing new mentoring programmes. Copyright © 1992 Carfax International Publishers.