The aims of this study were to establish and compare asymptomatic bacteriuria (ASB) in pregnant and non-pregnant women, to determine the agents of ASB in both groups and to investigate antibiotic sensitivity to agents of ASB. 323 pregnant and 75 non-pregnant women who were admitted to Erbaa State Hospital, Department of Obstetric and Gynecology Unit were included to the study. ASB was diagnosed in 22 pregnant (6.8%) and 4 (5.3%) non-pregnant women. It was not statistically significant. All pregnant women with ASB were treated according to antibiotic sensitivity of bacteria. To decrease acute pyelonephritis in pregnant women and to avoid maternal and fetal risks ascociated with ASB (premature delivery, premature rupture of membrane, delivery of low-birth weight fetus), all pregnant women should be investigated about ASB and all pregnant women with ASB should be treated with appropriate antibiotics. © 2012 Düzce Medical Journal.