The prevalence of asymptomatic bacteriuria among the pregnant women receiving antenatal care at Federal Medical Centre Owerri, Nigeria was studied using one hundred and forty urine samples from the pregnant women in the in-patient and outpatient departments. Thirty-five of the women had significant bacteriuria, with a prevalence rate of 25%. The bacteria in the samples were Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Proteus mirabilis. Escherichia coli occurred most frequently (40%) while Pseudomonas aeruginosa had the lowest frequency of occurrence (14%) in the samples. The infection was most prevalent among the women aged between 21 and 30 years (38.1%) and lowest among those between 41 and 50 years of age (9.4%). The prevalence was highest among the pregnant farmers and lowest among the pregnant civil servants in both the in-patient and outpatient departments. Pregnant women in the outpatient department had a higher prevalence than the women in the in-patient department. Pregnancy promotes the progression of asymptomatic to symptomatic bacteriuria with its consequences such as pyelonephritis, urinary tract infections and increased foetal mortality, therefore regular urine analysis of all pregnant women by certified health authorities is recommended.