The aim of this review is to identify the features of family planning service provision that are influential in ensuring safe and appropriate contraceptive use and optimal effectiveness of user-dependent methods. A systematic search was carried out of the published and unpublished studies available up to December 1997 that examined the relationship between family planning service provision and contraceptive use. Articles that reported primary data on long-term outcomes were scored by at least two of the authors of the present study. Particular attention was paid to evaluating methods of measuring quality of care. A total of 142 articles were identified, but only 16 reported primary data relating to long-term outcomes. The quality of provider--client exchanges was found to have a net incremental effect on contraceptive use. Evidence of effectiveness of methods to improve uptake, continuation of method use, and safe and appropriate use of fertility control is scant. The evidence that is available indicates that training in communication with clients (particularly about side-effects of contraceptive methods) and an emphasis on client choice are key components of effective interventions. The tasks of listening to clients, and tailoring services to local needs, are crucial to the success of family planning service provision.