The charts of 112 patients with small cell lung cancer were reviewed in a retrospective fashion in order to define the role of the radionuclide bone scan and bone marrow biopsy in the staging of this disease. Both a radionuclide bone scan and bone marrow biopsy were performed on all patients at the time of diagnosis. Sixty-one percent of patients had a negative bone scan and negative biopsy; 22% had a positive bone scan and negative biopsy; 8% had a negative scan and positive biopsy; and 9% had a positive scan and positive biopsy. In 21 of the 44 patients with osseous involvement, no other focus of distant metastasis was found. The bone scan showed greater than or equal to 3 areas of increased uptake in 15 patients, 2 areas of increased uptake in 13 patients, and 1 area in 7 patients. The number of patients with bone marrow biopsy results positive for tumor in these 3 groups were 5, 3, and 2, respectively. Our study shows a lack of correlation between bone scan and bone marrow biopsy results. The bone scan and bone marrow biopsy identify independent patterns of osseous metastasis. Both procedures should be performed in the evaluation of patients with small cell lung cancer.