The purpose of this article is to describe the usual procedure and postoperative recovery after an allogeneic bone marrow harvest and to present a case study of an unusual complication of hemorrhage. The case study describes a donor who experienced hemorrhage with severe pain, muscle spasms, and prolonged limitations in range of motion and ambulation. Oncology nurses should inform donors to promptly report persistent pain, spasms, and muscle weakness. Should hemorrhage occur, blood loss should be evaluated, bedrest should be maintained, and cold packs should be applied to the area. Although excessive bleeding is a rare occurrence, nurses should be alert for this complication to prevent pain and activity impairment.