PURPOSE OF REVIEW: Population-based investigations comprise a significant portion of the prostate cancer literature and contribute considerably to our knowledge of this disease. It is important to recognize, however, the inherent limitations of observational study designs. In this review, we will highlight important population-based studies in prostate cancer of high methodological quality using the framework of the recently published Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. RECENT FINDINGS: Recent findings of population-based studies of prostate cancer have generated key advances in our understanding of prostate cancer outcomes and epidemiology, which are highlighted in this review. The STROBE criteria, which were developed to promote the transparent reporting of observational studies, provide an excellent framework to determine the validity of conclusions drawn from large population-based studies. SUMMARY: Population-based research is a powerful tool for understanding prostate cancer, but clinicians and investigators must interpret findings appropriately.