Multiple agents have been suggested as urinary bladder carcinogens. Of these, certain aromatic amines and some tryptophan metabolites (Anthranilic acid, 3 hydroxy Anthranilic acid) have been proved to be carcinogenic. Others are suggested but are not conclusively proved as carcinogenic agents. Various animal species have been used as experimental models for the study of induction of cancer of the bladder and substantial progress has been made in the search for etiologic factors and pathogenesis of bladder tumors. A carcinogenic model of cancer bladder induction is proposed. However, knowledge of the tumorigenesis of cancer of the bladder is still limited and fragmentary. It appears, however, that Tryptophan dysmetabolism play a major role in this field and future experimental and epidemiologic studies should take this fact into consideration.