Twenty-one patients with 22 pathologic humeral fractures were seen between January 1977 and November 1988. All fractures were secondary to myeloma or metastatic disease. Primary bone tumors were not included. Nineteen of 22 fractures were treated with intramedullary fixation: 12 of these fractures were also treated with methylmethacrylate. Two patients had compression plating, and the remaining patient had no surgery. Twenty-eight percent had a previously undiagnosed malignancy. Postoperatively, 78% of the patients had only mild or moderate pain. Five patients had progression of local disease postoperatively, two resulting in failure of fixation. Both plates failed. Three patients required additional humeral procedures, one of which was a shoulder disarticulation for pain. Intramedullary fixation of pathologic fractures improves the quality of life by controlling pain for most patients. Complications, treatment failures, and pain are related to a 29% rate of tumor progression and a 23% rate of fixation failure.