A retrospective study of 146 patients with metastatic disease was undertaken to verify the clinical impression that radionuclide scanning rarely, if ever, discloses hepatic metastases in breast cancer patients with normal serum alkaline phosphatase (AP) levels. Only two of 39 patients with abnormal liver scans had normal AP levels, and we conclude that liver scans are not necessary as a routine screening method for liver metastases when the AP level is normal. In contrast AP levels were not predictive of bone scan results. All patients with a twofold or greater elevation of the AP level had abnormal bone, liver, or bone and liver scans. Routine AP determinations provide accurate staging information, and their proper use can decrease the cost of initial and follow-up examination of patients with breast cancer. © 1979, American Medical Association. All rights reserved.