Health status indicators for the population of Costa Rica compared favorably in the 1980s to those of more developed nations. Morbidity and mortality had been lowered, and health status differentials; between population subgroups had been narrowed. By 1984, most of the objectives set by the World Health Organization had been exceeded. These outcomes have been attributed to the success of a national primary health care program and to the role of the health assistant/asistente de salud in the operation of this program. This article examines the approach taken in achieving these outcomes. Of particular interest is the role of the health assistant as health educator in attaining the health promotion and disease prevention goals of the primary care program. Contemporary challenges which may diminish the role of the health assistant and the possible consequences of this for public health are considered, as isa recent government experiment which affords a potential response to these issues. The latter, a new model for the organization and delivery of health services, features a partnership between government and a private sector provider group. This arrangement retains the traditional role of the health assistant in primary care and enhances the health education function of the health assistant. Under pressure and in transition, the health sector in Costa Rica is striving to safeguard the admirable achievements it has attained and to plan for further advances. It is clear that under present circumstances difficult choices must be made. One hopes that in the trade-offs made, those elements of the primary health care program which have been essential to this nation's success are not assigned a lower priority.