Abstract : To assess the prevalence of asymptomatic bacteriuria in second trimester pregnant woman visiting tertiary care hospital and its effect on maternal and fetal morbidity. Clean catch midstream urine specimen of 506 pregnant woman belonging to 2nd trimester attending tertiary care hospital were collected in a sterile container and processes within 1 hour. If delayed, sample were refrigerated at 4degree celcius. Screening test such as wet mount, gram staining, hanging drop test were done. Cultures were done by semi quantitative method, nutrient agar, blood agar and cystine lactose electrolyte deficient medium(CLED) agar plates and incubated at 37degree Celsius for 24 hrs. Significant bacteriuria more than 1,00,000 CFU/ml of urine was confirmed by colony count. Organisms were identified and antibiotic sensitivity test of isolates were performed. Out of 506 pregnant women, 252 patients were identified by culture to have significant bacteriuria. Maximum patients belonged to age group (20-30 yrs) and highest percentage age of significant bacteriuria was identified in same age group. E.coli was most common organism followed by K.pnemonia. 15.82% was sensitie to ciprofloxacin followed by cotrimoxazole. The percentage of hydronephrosis is 10.29%. Incidence of oligohydrominos was found to be 16%. Onset of IUGR was found to be 5% higher in patient with asymptomatic bacteriuria. 21.9% babies were delivered preterm. Thus screening for Aymptomatic bacteriuria should be done in all 2nd trimester pregnant women and should be treated aggressively with suitable antibiotics to prevent various adverse events in pregnancy.