Background: The clinical spectrum of Brucella infection is quite diverse and characterized by multi-system involve-ment. Patients present with myocarditis, endocarditis, or pericarditis. Infective endocarditis is the most common cardiovascular complication in patients with brucellosis. Although conduction abnormalities are seen in cases with endocarditis, they are reported very rarely in the setting of cardiac Brucella infection.Case Report: An eight and a half-year-old male patient was referred to our clinic due to inadequate response to cotrimaxazole plus streptomycin treatment at the 15th day of admission. Although local hospital records on the patient showed a heart rate of 80 bpm, we determined a heart rate of 46 bpm. The electrocardiogram showed com-plete atrioventricular (AV) block. The average heart rate was determined as 48 bpm with 24-hour Holter electro-cardiogram (ECG) monitoring. The echocardiographic examination showed normal-sized heart chambers and the absence of valvular involvement. An agglutination test for brucellosis was found to be positive with a titer of 1/320. High fever, arthralgia, and splenomegaly regressed fol-lowing doxycycline plus rifampicin therapy, but there was no improvement in the AV block. A permanent pacemaker was implanted because of the detection of an average heart rate of 48 bpm.Conclusion: Because cardiac failure and rhythm abnor-malities are reported in the course of Brucella infection and may be associated with significant outcomes, cases with brucellosis should be evaluated carefully in terms of cardiac involvement. This report aims to draw attention to complete AV block as an extremely rare complication of Brucella infection