In two Russian studies (UTIAP-1 and UTIAP-2) susceptibility to commonly used antimicrobial agents for urinary tract infections (UTI) was determined. 456 urinary isolates were obtained from 588 out-patients with uncomplicated UTI in eight Russian centers during 1998-2001. The most common pathogens were Escherichia coli (85.9%) and Klebsiella pneumoniae (6.0%). Over 90% of the E. coli isolates were susceptible to nitrofurantoin (95.7%), cefuroxime (96.4%) and ciprofloxacin (95.5%). Co-amoxiclav, nalidixic acid and pipemidic acid were less active -84.4%, 93.1% and 93.9% susceptibility stains correspondingly. In contrast, 37.1% of the E. coli isolates were resistant to ampicillin, 22.9% to trimethoprim, 21% to co-trimoxazole. Susceptibility patterns of uropathogens vary between geographical regions of Russia.