A serological study of toxoplasmosis was conducted between 1996 and 1998 on 1953 patients of the Medical Analysis Laboratory of the Institut Pasteur de Bangui. The mean age of patients was 28 years. Among sera tested by ELISA, seropositivity to IgG antibodies was observed in 50.6%, and 2.6% sera were found positive for IgM antitoxoplasma antibodies (immuno-capture). The seroprevalence did not vary significantly according to sex or age. The results showed 40.8% sera had IgG antibodies titered 400 Ul/ml and more. The proportion of high level (> 400 Ul) IgG was more important in males than in females. High level IgG antibodies were statistically significant more frequently in the sera of females aged 10-29 years. Of the procreative women, 49.1% were at risk of contacting toxoplasmosis. The diagnosis of recently acquired infection, based on the coexistence of IgM antibodies and high level IgG antibodies, was noted in 1.6% among sera of procreative women. In the Central African Republic, serologic survey during pregnancy is not systematic and HIV seroprevalence is high (15%). Risks of acute infections during pregnancy and of opportunistic infections in HIV-infection patients are high. A control of toxoplasmosis is justifiable (screening during pregnancy, sanitary education) in CAR.