This book contain the first trial for proving the association between Mycobacterium tuberculosis (MTB) infection and urinary bladder carcinoma. Many studies mentioned the role of chronic Escherichia coli (E. coli) infection and some factors as a risk factor for bladder cancer but there were no study investigated the role of chronic MTB infection. There are many cellular and humoral responses that occur during chronic Mycobacterial infection may give chance for neoplastic changes in the urothelial cells we tried to review some of these responses and their mechanisms that may enhance malignancy. In this humble work we used molecular techniques to detect MTB in Bladder cancer patients and in other patients. This work is a beginning for a future work that require more investigatory and follow-up studies.