Peer review is a basic component of the scientific process, but its performance has seldom been evaluated systematically. To determine whether pre-approval characteristics of research projects predicted the performance of projects, we conducted a retrospective cohort study of all 2744 single-centre research projects financed by the Spanish Health Research Fund since 1988 and completed before 1996. Peer review scores of grant applications were significant predictors of performance of funded projects, and the likelihood of production was also higher for projects with a basic research component, longer duration, higher budget or a financed research fellow. Funding agencies should monitor their selection process and assess the performance of funded projects to design future strategies in supporting health sciences research.