BACKGROUND: It has been suggested that changes in prostate-specific antigen (PSA) over time (ie, PSA velocity [PSAV]) aid prostate cancer detection. Some guidelines do incorporate PSAV cut points as an indication for biopsy. OBJECTIVE: To evaluate whether PSAV enhances prediction of biopsy outcome in a large, representative, population-based cohort. DESIGN, SETTING, AND PARTICIPANTS: There were 2742 screening-arm participants with PSA /=3 ng/ml, we found little justification for formal calculation of PSAV or for use of PSAV cut points to determine biopsy. Informal assessment of PSAV will likely aid clinical judgment, such as a sudden rise in PSA suggesting prostatitis, which could be further evaluated before biopsy.