To study the influence of some urinary constituents on the adhesion ability of Escherichia coli to uroepithelial cells, a standard piliated strain (E. coli 31-B), its mutant lacking in type I pill (E. coli BH-5), and a wild-type laboratory E. coli isolate of serotype O4 possessing both MR and MS pill were used. The average number of bacteria adhering per uroepithelial cell was greater when grown in tryptone soya broth (TSB), compared with Fe-CDM grown strains. A similar effect was observed when strains were grown under iron-deficient conditions. Urinary constituents such as glucose, lactose, urea, and creatinine singly, or in combination, at different concentrations, when added to Fe-CDM medium, altered the adhesion potential of the growing organism. This effect, however, was strain-dependent. Its implication in the clinical set-up is discussed.