Many developing countries, particularly in Africa, have recently introduced payment schedules based on the selling of essential drugs. This is one of the main elements of the Bamako Initiative according to which the income generated would ensure a reliable supply of drugs and would improve other aspects of the quality of the services offered. Thus, quality improvements would compensate for the financial barrier and as a result the utilization of public health services would be increased or at least maintained. These hypotheses have proven to be partially valid, since there have been cases where the utilization of health services has increased and others where it has decreased; these inconclusive results have fuelled criticisms concerning the inequitable nature of these measures. This longitudinal study in a rural community of Zaïre shows that the utilization of health services had diminished by close to 40% over 5 yr (1987-1991) and that 18-32% of this decrease is explained by cost. The regular supply of drugs and the improvement in the technical quality of the services--technical qualification of the staff, allocation of microscopes, and renovation of the infrastructures--was not enough to compensate for the additional financial barriers created by the increased cost of services. However, on a local level, the interpersonal qualities displayed by some of the nurses sometimes helped to compensate for the negative effects of the costs, and even to increase the level of utilization of some health centres. The quality of public services has often been neglected in developing countries. While some attention is given to technical qualities, the interpersonal components of the quality of the services are generally ignored or underestimated by planners and they are the very components which are most resistant to change. It will be a major challenge for health systems to address this issue of quality of care in order to minimize the negative impact of the introduction of user payment schemes. Therefore, now is the time to place quality next to coverage in planners' agendas.