A national prevalence survey of leprosy was made in june 1989 in Popular Republic of Congo: authors report results. The prevalence rate is 5.8% +/- 2.6% among people more than 15 years of age, and 10.5% of all forms are multibacillary. All patients are under DDS monotherapy. One overwhelming risk factor is leprosy antecedents in the family history; active case-finding and surveillance of contacts are recommended.