The prevalence of asymptomatic bacteriuria and the relation of bacteriuria to pyuria, glycosuria and HbA1c in patients with diabetes mellitus were investigated. The study population included 110 diabetic patients and 100 healthy persons (control group). The ratio of bacteriuria was found as 25.5% (31.3% in women, 17.4% in men) in the diabetic group and as 9% (16% in women, 0% in men) in the control group. The prevalence of asymptomatic bacteriuria was significantly higher in the diabetic patients than in the control group (p less than 0.05). There was a significant relation between bacteriuria, pyuria and HbA1c levels (p less than 0.05). But, there wasn't any important correlation between bacteriuria and glycosuria.