Attempts were made to assess the value of various methods of demonstration of bone metastases in patients with recurrence of cancer of the breast. A material of 123 patients with suspected or verified recurrence of cancer of the breast was submitted to a programme of investigation consisting of conventional X-ray survey of the axial skeleton and thorax, bone tissue scintigraphy, bone marrow scintigraphy, bone biopsy and aspiration of marrow and blood status including serum alkaline phosphatase. 54% and 29% of the patients had bone, metastases as assessed radiographically and by biopsy, respectively. In patients with radiographically demonstrated bone metastases, the predictive value of positive (PV-pos) whole-body scintigraphy was 79%. The findings on bone tissue scintigraphy and bone marrow scintigraphy were in agreement with the radiographic findings in 78% and 72%, respectively, and with the biopsy findings in 71% and 74%, respectively, of the cases. All of the cases of metastases verified by biopsy were identified also by radiographic examination and by bone tissue scintigraphy. The predictive value of negative bone tissue scintigraphy (PV-neg) was 76% and of bone marrow scintigraphy 65%. With biopsy as the final proof, bone tissue scintigraphy, bone marrow scintigraphy and radiography were found to have PV-pos values of 96%, 89% and 95%, respectively and PV-neg values of approximately 50% for all three forms of examination. Bone marrow scintigraphy has thus no diagnostic advantages as compared with bone tissue scintigraphy.(ABSTRACT TRUNCATED AT 250 WORDS)