Immunotherapy of bladder cancer with non specific immunostimulants, such as bacillus Calmette Guerin (BCG), has been shown to significantly reduce tumor recurrences, and, when applied through intravesical BCG instillation to induce the regression of some established tumors, including carcinomas "in situ" and even some invasive tumors. Since in other tumors, namely melanomas, BCG has been proved to be most successful when infected directly into the tumor, intralesional therapy with BCG (1.5 x 10 BCG weekly for four weeks) has been applied in 20 patients affected by bladder cancer (T1 - T2). The local reaction has induced substantial reduction of the tumor mass and, in some cases, (four) total disappearance of the tumor. On the sixteen patients without total disappearance of the tumor, TUR was applied. The successive follow-up of these patients offer at present the following figures: 3 out of the four patients with remission after BCG alone are disease-free after 26-30 months, whereas one has developed after 18 months a papilloma surgically removed; 15 out of the sixteen patients treated with BCG followed by TUR are disease-free after 26-30 months. These data, compared with literature findings, support the idea that intratumoral BCG instillation of bladder cancer permits a longer disease-free period than other therapeutical approaches.