Large cell neuroendocrine carcinoma of the urinary bladder is rare. In the last five years, we have had the opportunity to see this type of cancer in an 88-year-old and in a 66-year-old males. In both cases, transurethral resection of carcinoma of the bladder was carried out. In the first case, urothelial carcinoma was detected and deeper in the bladder wall, large cell neuroendocrine carcinoma structures were found. In the second case, the bladder was only infiltrated with large cell neuroendocrine carcinoma. Both tumors expressed NSE, CD56 and synaptophysin. Other markers, such as those against calcitonin, chromogranin, PP, VIP, serotonin, gastrin, glucagon and somatostatin did not react with the tumor. In the first case, no tumor dissemination was found; in the second case, clinical methods confirmed dissemination into the liver, left adrenal gland, spleen and paracaval lymph nodes. Given his age, the first patient only received symptomatic therapy. The other patient underwent chemotherapy and his condition is stable. Paraneoplastic manifestations of the tumors were not clinically found. Histogenetic origin of neuroendocrine tumors is not fully clarified. In some cases, tumor development is thought to be associated with Brunns nests, cystitis cystica and urothelial carcinoma stem cells.