Uterine cervical carcinoma secondarily involving the genitourinary tract is rarely documented histologically. These tumors present a unique diagnostic challenge as they can appear morphologically similar to urothelial carcinoma as well as primary squamous cell carcinoma and primary adenocarcinoma of the bladder. Genitourinary consult cases at the Johns Hopkins Hospital from 1984 to the present were searched for cases in which the differential diagnosis was primary bladder carcinoma versus secondary involvement by cervical carcinoma. We identified 10 cases that met these criteria and evaluated them by immunohistochemistry for p16 and GATA3 and in situ hybridization for human papillomavirus (HPV). Six cases were received with a gynecologic history. Four cases had been misdiagnosed as urothelial carcinoma, and 1 case was favored to be cystitis cystica et glandularis by the submitting institutions. Morphologically, the majority of cases showed basaloid nests of tumor cells infiltrating muscle bundles, with several having foci that mimicked urothelial carcinoma in situ. Six tumors were found to be diffusely positive with p16, 1 tumor was patchy, 1 was weak, and 2 were negative. GATA3 staining was negative in 6 cases, and 4 showed weak to strong positivity. Eight cases were positive for high-risk HPV (6 were positive for HPV 16, and 1 was positive for HPV 18). In the 2 cases that were negative for HPV by in situ hybridization, characteristic morphologic features of HPV-unrelated type of endocervical adenocarcinoma were present. On the basis of our findings we advocate a multifaceted approach, combining morphologic evaluation with ancillary studies including immunohistochemistry and in situ hybridization in the evaluation of genitourinary specimens for secondary involvement by cervical carcinoma. Furthermore, gynecologic clinical history is absolutely critical and most important to the evaluation and diagnosis of these specimens, as these ancillary studies are not completely sensitive or specific.