Chemotherapeutic agents that bind tubulin cause mitotic arrest, which may be seen histologically. Such mitotic arrest has been reported to occur in the skin, alimentary canal, lungs, liver, bone marrow, endometrium, breasts, or in ascites following treatment with paclitaxel, vincristine, colchicine, podophyllotoxin, or maytansine. Mitotic arrest as a result of docetaxel, a taxane that binds tubulin, has yet to be reported. Mitotic arrest in the gallbladder has also yet to be reported. We recently encountered a case of dramatic mitotic arrest as a result of docetaxel, involving the gallbladder of a 66-year-old man with metastatic bronchogenic carcinoma. Strikingly abundant bizarre mitoses initially prompted a diagnosis of primary carcinoma. Carcinoma was eventually excluded based on the absence of dysplasia in all cells at interphase and the history of recent administration of docetaxel. This is the first case of mitotic arrest involving docetaxel or the gallbladder. Awareness of this phenomenon is necessary to avoid misdiagnosing carcinoma.