We report the cases of 11 patients who were treated for undifferentiated carcinoma of the urinary bladder with a prominent lymphoid stroma (lymphoepithelioma-like carcinoma [LELC]). The chief complaint of all 11 patients was hematuria. Their ages ranged from 52 to 79 years (mean of 67). All tumors except one invaded the muscle wall and showed the typical syncytial growth pattern of undifferentiated cells with ill-defined cytoplasmic borders, prominent nucleoli, and numerous mitoses. A significant lymphocytic reaction was an essential component of all these tumors. There were three pure LELC tumors without concurrent invasive transitional-cell carcinoma (TCC) or TCC in situ; these cases morphologically simulated large-cell lymphoma. The remainder were mixed TCC and LELC (five predominant and three focal LELC). The tumor cells were immunoreactive for keratin and showed negative results for leukocyte common antigen. The lymphoid population was an admixture of T cells and B cells with a predominance of T cells. Seven patients (four with predominant and three with focal LELC) were treated with various therapeutic methods. Four patients (three with pure and one with predominantly LELC) received only chemotherapy after transurethral resection of the tumor, and follow-up found no evidence of disease for 9–72 months (mean of 38 months). Awareness of an LELC component in a urinary bladder tumor is also important in order to avoid misinterpreting these tumors as malignant lymphoma or severe chronic cystitis. Our data suggest that the pure LELC tumor appears to be morphologically and clinically different from TCC and that it merits recognition as a separate clinico-pathologic entity. In addition, there is strong suggestive evidence that it responds to chemotherapy and therefore there is the potential of salvaging bladder function.