The objective of this study was to evaluate the budget impact of a new prostate cancer risk index for detecting prostate cancer. The index is calculated as the combination of serum prostate-specific antigen (PSA), free PSA and a precursor form p2PSA. We constructed two budget impact models using PSA cutoff values of ≥2 ng ml(-1) (model #1) and ≥4 ng ml(-1) (model #2) for recommending a prostate biopsy in a hypothetical health plan with 100 000 male members aged 50-75 years old. The budgetary impact on the 1-year expected total costs for prostate cancer detection was calculated. Adding the index to the current PSA prostate cancer testing strategies including the total PSA and percent free PSA, the number of detected cancer cases decreased by 20 and 5, in models #1 and #2, respectively. The savings on expected 1-year cost for prostate cancer detection were $356 647 (or $0.30 per-member-per-month (PMPM)) in model #1 and $94 219 ($0.08 PMPM) in model #2. The index produced higher cost savings in the model #1 with PSA cutoff ≥2 ng ml(-1) than the model #2 with cutoff ≥4 ng ml(-1) with a small short-term reduction in the number of positive tests.