The Central African Republic, which once had the highest Hansen disease prevalence rate in the Central African States, had exemplary results in the control carried out on the basis of sulfonic monotherapy since 1958. In 1983, a cluster sample survey in Upper-Sangha seemed to show that the prevalence of the disease was underestimated. It then became necessary to adopt a new national strategy whose objective would be to reduce the prevalence of leprosy in the country by 50% within five years. For this, a "National Programme for the Control of Leprosy in C.A.R." has been developed; in part it foresees the setting up of polychemotherapy for patients. These treatment protocols should insure healing of paucibacillary forms within six months and of multibacillary forms within twenty-four months. The new strategy of screening and decentralized treatment required retraining personnel and combining health education at individual and collective levels. The preliminary results of a national survey for the evaluation of the prevalence of leprosy are presented.