Early diagnosis of organ involvement and bacteremia in brucellosis increases treatment success and may prevent poor clinical outcomes. This study aimed to investigate the predictors of focal involvement and bacteremia in patients with brucellosis. A total of 139 brucellosis patients aged 16years and older were included in the study. Patients with and without organ involvement and bacteremic and non-bacteremic patients were compared separately. Low back pain, lymphadenomegaly, absence of fever on admission, ESR, AST, and neutrophil-lymphocyte ratio (NLR) were predictors of focal involvement (OR: 2.604; 3.167; 7.224; 1.039; 1.032; 1.738, respectively). The AUC value of ESR was 0.669 (0.573-0.765, p = 0.002) with the cutoff point > 30mm/h (sensitivity 89.74% and specificity 37.00%) in predicting focal involvement in patients with brucellosis. Myalgia and headache (OR: 2.970; 2692) were defined as clinical predictors of Brucella bacteremia. Focal involvement should be considered in patients with brucellosis in the absence of myalgia and fever, presence oflow back pain, and sedimentation > 30mm/h. Brucella bacteremia should be considered regardless of fever, especially in patients with myalgia and headache in endemic areas.