From the perspective of the health care system, the health gains are too uncertain to justify the adverse health effects and the use of resources which would be associated with screening for prostate cancer based on PSA. Furthermore, the extent of the benefit which might result is relatively small. This is equally true for an organized comprehensive screening programme as it is for such screening as presently takes place in the context of case-finding. From the perspective of the individual whether a man, without special reason, should agree to (or insist on ?) the measurement of PSA is a decision with important consequences which each man should consider carefully in consultation with his medical advisor. Before his PSA is measured, such a man should be made fully aware of the possible results of undertaking this test.