OBJECTIVE To determine the frequency and risk factors of asymptomatic bacteriuria during pregnancy. METHODS Cross-sectional study. METHODS Satellite Town and Behari Colony, Bahawalpur from October 2001 to March 2002. METHODS There were 3000 houses in Satellite Town and Behari Colony, Bahawalpur. Taking 40% of total, 1200 houses were selected by systemic random sampling. Pregnant residents of these houses were included in the study. Data collected was coded, computed and analyzed on SPSS version 10. Frequencies were runned and chi-square test was used as test of significance. RESULTS Five hundred and eighty women, fulfilling the inclusion criteria, were interviewed and tested for bacteriuria. Out of them, 4% were below 20 years, 4.6% were between 20-30 years and 5.4% women aged above 30 years (p=0.103). Regarding parity 3.18 % of primigravidae and 6.04 % multigravida had bacteriuria (p=0.0039). Regarding socioeconomic status, 6.45% from lower class and 2.5% from middle and upper middle class were the sufferer (p=0.0039). Prevalence was 6.64% among uneducated and 3.06% among educated women (p=0.0039). As for past history, 35.7% of women had an episode previously (p=0.001). No association was found with anaemia. CONCLUSIONS Asymptomatic bacteriuria is a common infection during pregnancy, having strong association with multiparity, lower socioeconomic status and illiteracy.