A considerable amount of experimental, clinical and epidemiological data indicate that dietary fats play a role in urinary tract tumorigenesis. In rodents, chronic essential fatty acid (EFA) deficiency seems to induce both urolithiasis and transitional hyperplasias, followed by a tendency for tumorigenesis of the urinary passages. High intake of saturated fats or non-EFAs, conditions that may induce EFA deficiency (EFAD) increase the risk of bladder cancer in case-control studies. In other cell populations, EFAs are beneficial as preventive and therapeutic nutrients for the treatment of cancer. Thus, it is reasonable to assume that abnormal metabolism and/or nutritional deprivation of EFA, by inducing a chronic or a subclinical EFA deficiency, may enhance the risk of urothelial tumorigenesis.