The research was to determine the prevalence of Urinary Tract Infection as a cause of lower abdominal pains among antenatal women, its aetiological microorganism and define the sensitivity pattern to antibiotics.This was a cross sectional study with a sample size of one hundred and fifty antenatal women at Kenyattta National Hospital, Nairobi, Kenya. The prevalence of urinary tract infection was found to 26.7%. The predominant bacterial pathogens were Esherichia coli at 40% folowed by Staphylococcus spp. at 25% and Klebsiellla spp. at 10%. The gram positive isolated were 100% sensitive to Amoclauvulin, cefuroxime, cefuroxime, cetriaxone, meropenem and imipenem but showed significant resistance to levofloxacin, gentamycin, nitrofurantoin, and ampicilin.