Summary: We combined data from 20 years of the Finnish Randomised study of Screening for Prostate Cancer (FinRSPC) with information on costs and effectiveness from national registries. In addition to examining cost-effectiveness in terms of overall mortality, we also examined it in terms of diagnosed men’s mortality from prostate cancer and mortality with, but not from, prostate cancer. Although we found that mass screening likely helps to avert just over one prostate-cancer death per 1000 men screened, we also found five additional non-prostate-cancer deaths among diagnosed men, per 1000 men screened. These findings should be corroborated or contradicted by similar analyses using data from other trials, in order to reveal if more diagnosed men have also died elsewhere.