During a serosurveillance survey carried out from July to August 2005 in Ivory Coast, 660 sera were collected in the administrative regions of N’Zi Comoe and Lacs, in the central part of the country. The sera were used to determine the real prevalence of bovine brucellosis using a Bayesian framework with four serological diagnostic tests: slow agglutination of Wright (SAW), rose bengale test (RBT), indirect ELISA (iELISA) and complement fixation test (CFT). CFT results were not taken into account in the study. The serological analyses showed individual seroprevalences of 6.2% with SAW, 5.1% with RBT and 7.0% with iELISA. The Bayesian analysis performed with the same serological results helped to estimate at 8.8% the real prevalence of brucellosis (credibility interval of 95%: 5.0–16.4). Results show the importance of brucellosis in this part of Ivory Coast and confirm the attention that must be given to the disease.