This is a prospective study to determine the prevalence of asymptomatic bacteriuria among pregnant women attending their first pre-natal care visit at the antenatal clinic of the Central Hospital, Benin City, , the microbiological patterns and their susceptibility tests, and pregnancy outcomes after antibiotic treatment and the association of age, parity and socio-economic status with asymptomatic bacteriuria in pregnancy Pregnant women with no history of fever, no genitourinary complaints, and without any intake of antibiotics for any indication during the current pregnancy were included in the study. They were asked to submit urine specimens for routine urinalysis, urine Gram stain, and culture and sensitivity tests. Screening of urine specimen from each pregnant woman was done twice throughout the duration of pregnancy and the patients were followed up. A total of 276 apparently healthy pregnant women were screened after obtaining verbal consent to be included in the study. One hundred and seventy two had no pus cells in their urine samples with 11 showing significant bacteriuria, 76 samples contained 1 – 4 pus cells/high power field with 6 showing significant bacteriuria, while 28 samples had >5 pus cells/hpf with 3 showing significant bacteriuria. The prevalence of asymptomatic bacteriuria in the study was 7.2%. Escherichia coli was the second commonest organism isolated in the study (35%) after Staphylococcus aureus (40%). Other isolates include Klebsiella (10%), and 5% respectively for Bacteroides, Proteus mirabilis and Staphylococcus saprophyticus. Bacterial isolates in this study were more sensitive to ceftaxidine, followed by ceftriazone, and least sensitive to cotrimoxazole. There was strong association between increasing parity and low level of education or low socioeconomic status and asymptomatic bacteriuria. The benefit of treating asymptomatic bacteriuria in pregnancy was demonstrated in the study as the rate of adverse pregnancy complications was significantly reduced with treatment. Screening for and treatment of asymptomatic bacteriuria in pregnant women must be considered as an essential part of antenatal care as the long- term benefits of doing so cannot be overemphasized