Recent reports suggest that radionuclide bone scan (BS) may not be necessary in the standard staging evaluation of patients with prostate cancer when serum prostate-specific antigen (PSA) levels are normal. To evaluate the ability of PSA to predict BS findings, we retrospectively reviewed the case records of 118 consecutive patients (median age 73 years, range 50-90 years) with newly diagnosed, untreated, pathologically proven prostate cancer who underwent BS and serum PSA sampling within a period of no more than 3 months. Fifty-four out of 118 BSs demonstrated metastatic bone disease. A PSA value of less than 10 ng/ml excluded bone metastasis; of 35 patients with a serum PSA level of 20 ng/ml or less, seven had a positive BS (negative predictive value of 80%). These findings provide additional confirmation of the value of low serum PSA concentrations in excluding the need for a staging BS, although the threshold for a high value of negative predictive accuracy is lower than previously reported.