Sixty-six sera from HIV-1-seropositive adult African subjects and 49 sera from HIV-seronegative age and sex matched healthy African controls living in Bangui, Central African Republic, were screened for Coxiella burnetii antibody by an indirect immunofluorescent antibody test. 16.7% of HIV-infected patients and 16.3% of the HIV-negative controls had positive IgG titres, with no significant difference between the two groups. Two of the seven HIV-infected patients seropositive for Coxiella burnetii for whom clinical data was available had a medical history compatible with symptomatic Q fever. These findings indicate that there is a high degree of exposure to Coxiella burnetii infection in Bangui. In individuals co-infected with HIV and Coxiella burnetii, cellular immunosuppression could favour symptomatic Q fever. Physicians should be aware of the possibility of symptomatic Coxiella burnetii infection among HIV-infected people, particularly in endemic regions for both infections such as in sub-saharan Africa.