Of 297 patients with metastatic testicular and extragonadal germ cell tumours (GCT), bone involvement was detected clinically in 3% (7/251) of those at first presentation and in 9% (4/46) of relapsed cases. This difference was not statistically significant (95% confidence limits -2%; +14%). Concurrent systemic metastases, commonly involving lung (7/11 cases) and para-aortic lymph nodes (6/11), were present in all patients with bone disease. All affected patients had localized bone pain and lumbar spine was the most frequent site involved (9/11). Spinal cord compression occurred in two patients while a third developed progressive vertebral collapse after chemotherapy and required extensive surgical reconstruction. At median follow-up of 4 years, survival among patients presenting with bone disease (6/7) was similar to overall survival in the whole group (84%) and appeared better than in those with liver (18/26, 69%) or central nervous system (6/9) metastases at presentation. Back pain in metastatic germ cell tumours is often due to retroperitoneal lymphadenopathy but lumbar spine osseus metastases must be recognized early if severe potential complications, such as spinal cord compression, are to be avoided. In this series, bone metastases were not seen in the absence of widespread systemic disease suggesting all solitary bony lesions in GCT patients should be biopsied.