The frequency of nine potential Escherichia coli urinary tract infection (UTI) virulence factors was investigated among 216 isolates from 208 women 18-40 years old with first-time UTI. Factors were afimbrial adhesions I-IV and F1845 pili (drb), aerobactin (aer), group II capsules (kpsMT), cytotoxic necrotizing factor 1 (cnf1), alpha-hemolysin (hly), outer membrane protease T (ompT), Pap and Prs pili (prf), S fimbriae (sfa), and type 1 pili (fim). Women were enrolled at two sites. Pairwise comparisons found 14 statistically significant associations between virulence genes after correcting for multiple comparisons. This is the first report of five associations: aer and drb, kpsMT and ompT, ompT and cnf1, ompT and sfa, and prf and ompT. As ompT is not closely linked genetically to kpsMT, cnf1, prf, or sfa, ompT may be functionally linked with one or more of these other virulence factors.