Most of the complications caused by asymptomatic bacteriuria (ABU) in pregnancy can be avoided by early treatment. In our study, we aimed to determine the urinary infection prevalence and the pathogen agent identification in the pregnant women observing in our clinic. 240 asymptomatic pregnant women having no antibiotic treatment history during last 1 week and were enrolled to the study. Urine specimens were collected from 12th and 16th week pregnant women, and were examined by light microscope and cultured at the mediums. Demographic data belonging to the patients (age, birth number, abortion number) were recorded. Mean age was assigned as 24, 49 +/- 2, 74 (20-31 years). 104 patients (%43,3) were primipara, 94 patients (%39.2) had previous pregnancy and 42 patients (%17,5) were multipara. %19,2 of the patients (n=46) had an abortion history. Mean value of leucocyte levels among pregnant women was assigned as 10045 / mm3 (6750-15200). Although positive urine culture ratio was %12,5 (n=30) at first visit, it was %10 (n=30) in the 12th week. Urine culture in 16th week was determined as negative in all pregnant women. When agent pathogen was analyzed from urine culture, the most common isolated microorganism that causes asymptomatic bacteriuria (ABU) was Escherichia coli with ratio of %83(n=200). Asymptomatic bacteriuria (ABU) is common in pregnancy and can cause serious maternal and fetal complications if it's not treated on time and properly. Therefore; all pregnant women should be screened at first antenatal visit for asymptomatic bacteriuria (ABU) as a routine program and medical treatment should be required at the positive cases.