Screening for prostate cancer has been advocated by a number of organisations largely because there is good evidence that administration of the test for prostate specific antigen (PSA) results in the detection of cancers at an early stage. However, the mere fact that a cancer can be detected earlier in its natural history by screening is no guarantee that benefit will follow. Further, screening for prostate cancer can substantially impair the quality of life of those with detected and treated cancer, that would not otherwise have reduced life expectancy. The only established mechanism to evaluate the efficacy of screening is the randomised controlled trial. In this paper we review the trials contributing to our collaboration, the advantages that will flow from them, and the reasons why decisions on the introduction of population-based screening for prostate cancer cannot be made before these trials have come to fruition.