Brucellosis is the most common worldwide zoonotic infection of which psychosis is a rare feature of this disease. Brucellar psychosis should be considered in a patient with unexplained, nonspecific psychological complaints. Its timely diagnosis relies on special attention to the epidemiologic profile of the patient for a possible exposure to the brucella species. This article has presented three cases of brucellar psychosis initially misdiagnosed because the risk factors which made them at risk for the disease were ignored.