During the last decade consideration of the role of vitamins and minerals in primary prevention of genitourinary tumors has changed dramatically. Despite all efforts the efficacy of a specific compound has not yet been proven and as a consequence recommendations for the use of vitamins or other supplements for tumor prevention should no longer be given. In contrast life style modification might be helpful as recent investigations suggested that smoking not only promotes the development of bladder cancer but is also involved in prostate and renal cell carcinogenesis. In addition there is some evidence that moderate food consumption, reduction of dairy product consumption and an Asian or Mediterranean diet can prevent prostate cancer and also harbor additional beneficial effects for general health. These observations should be the starting point of future epidemiological research. This may be considered as a change of paradigm in prostate cancer prevention. In contrast there is clear evidence of the efficacy of chemoprevention using 5α-reductase inhibitors as the use of finasteride and dutasteride significantly reduces the detection of prostate cancer. However, translation of these findings into urological practice remains a matter of controversial discussion.