The potential role of rock pigeons (Columba livia) in the epidemiology of shiga toxin– producing Escherichia coli (STEC) and Salmonella enterica is unclear. Our objective was to determine the prevalence of STEC and S. enterica in pigeons at urban and dairy settings as a function of season. Prevalence of STEC and S. enterica was estimated by bacteriologic culture of cloacal swabs collected from pigeons trapped at urban and dairy locations in and around Fort Collins, Colorado from January to November 2003. Presumptive E. coli isolates were tested for the presence of virulence genes SLT-1, SLT-2, eae, hlyA, K1, CNF-1, CNF-2, and LT using polymerase chain reaction. Shiga toxins were not isolated from any of 406 samples from pigeons, but virulence genes typically associated with disease in humans were identified in isolates from 7.9% (95% CI: 5.5% to 10.9%) of captured pigeons. S. enterica were detected in 3.2% of 277 samples from pigeons, with all positive samples originating from dairy locations (nine of 106 [8.5%]; 95% CI: 4.0–15.5%). The results suggest that although pigeons may acquire S. enterica from cattle and play a role in recirculation and persistence of the microorganism at dairies, pigeons are not important carriers of STEC.