This study of the Family Planning Fieldworker (PLKB) in West Java province, Indonesia, has been conducted in the framework of the Serpong Family Planning Research and Training Project, an interdisciplinary co-operation between the University of Indonesia in Jakarta and the University of Leiden in The Netherlands. and a number of government and private organizations participated. The main objectives of the project, of which the field-period lasted from February 1972-April 1975, were to conduct : an analysis of the social, cultural and economic factors influencing fertility and the acceptance of family planning, an analysis and evaluation of the introduction of family planning by Indonesian organizations, methods used and the development of alternative methods, interdisciplinary training of medical and sociological students in the field of family planning, a medical analysis and evaluation of traditional and modern contraceptive means and methods, and evaluation of the health centre as a family planning unit.