Simple bone cyst (SBC) is a benign fluid-filled cavity found primarily at the proximal ends of long bones in children. Treatments proposed for SBC range from observation to intralesional curettage and bone grafting, which are all associated with uncertainty and complications. Because of these factors, a relatively noninvasive protocol with osteoinductive autogenic bone marrow was instituted. Twelve patients were identified with SBCs. Bone marrow was aspirated from the patient's iliac crests and injected into the cyst cavity. Follow-up ranged from 9 to 57 months. Eight (67%) patients demonstrated substantial healing, two (17%) showed partial healing, and two (17%) did not respond to bone marrow therapy. The advantages suggested by bone marrow injection over the currently practiced methods include a higher success rate with a single injection and earlier healing.