When large soft-tissue and osseous defects remain after debridement of a chronic osteomyelitic lesion, application of a local muscle flap can be an effective way to achieve wound closure. Utilizing this surgical technique and specific antimicrobial therapy for the causal microorganisms, the infectious process was eradicated in thirty-nine of forty-two patients with osteomyelitis who were followed for at least two years after treatment. The osteomyelitic process was post-traumatic in origin--that is, a complication of a fracture or its treatment--in twenty-eight patients, the result of soft-tissue trauma without a fracture in eight, a complication of elective surgery in three, and the result of hematogenous seeding in three patients. Nine of the forty-two patients had an infected non-union. The infectious process involved the tibia in 62 per cent of the patients. Pseudomonas aeruginosa was the most frequently isolated causal organism. A soleus or gastrocnemius muscle flap was most frequently utilized to achieve closure. In five patients, a combination of two muscle flaps was utilized. Although this technique successfully eradicated the infectious process in 93 per cent of the patients, twenty-two patients required additional surgical treatment. Six required such treatment for a persistent non-union and two, for weakened diaphyseal bone after eradication of the septic process. A cancellous bone-grafting procedure was performed in all eight patients after the muscle flap had healed, and union was achieved in six of them. One patient eventually requested an amputation for a persistent non-union, and the remaining patient had a fibular synostosis performed for a persistent tibial non-union. A local muscle flap can be used in patients with a large defect of soft tissue and bone after debridement of an osteomyelitic lesion if the flap can be elevated and transposed into the defect without compromising its vascular supply. Although they are not applicable to the treatment of all patients with osteomyelitis, local muscle flaps can be extremely useful in the treatment of this lesion. When combined with thorough debridement and specific antimicrobial therapy, it has become a successful technique in the management of chronic osteomyelitis.