No data are available concerning the seroprevalence of brucellosis in Central African Republic (CAR) and the last report concerning the seroprevalence of Q fever in CAR is from 1995. The aim of our study was to determine the prevalence of these diseases in CAR, especially in Zebu cattle. We used the Rose Bengal Plate Test to test 2032 bovine serum samples for antibodies to Brucella spp. and an indirect immunofluorescence assay to test 784 bovine serum samples for antibodies to Coxiella burnetii (the species responsible for Q fever). The mean seroprevalences of antibodies to Brucella and Coxiella were 3.3 and 14.3%, respectively. Significant differences were found between regions and herds for both diseases. However, relation with differences of climate or vegetation were not evident. Therefore, further data are necessary to better understand the epidemiology of these diseases in CAR and evaluate losses to the farmers.