Twelve patients with skeletal metastases from occult primary carcinomas were evaluated in an effort to develop an efficient routine for detecting the primary tumor in such cases. In all of the cases the initial medical histories, physical examinations, and laboratory tests failed to detect the site of the primary carcinomas. The primary sites in five patients were identified by simple imaging studies; three patients had hypernephromas and two had lung carcinomas. In spite of subsequent extensive diagnostic testing, the primary site was identified antemortem in only one additional patient. A routine strategy has been designed for locating skeletal metastases and detecting the primary site of a carcinoma. If this routine does not identify the patient's primary site, no further diagnostic tests need be performed.