Preliminary reports have indicated that debridement of the bony sequestrum followed by muscle-flap coverage allows successful treatment of chronic osteomyelitis. To determine the long-term effectiveness of this procedure, 34 consecutive patients with chronic osteomyelitis of the distal lower extremity treated with debridement, a 10- to 14-day course of culture-specific antibiotics, and immediate muscle-flap coverage were evaluated. Patients were treated from 1979 through 1984, and long-term (greater than 5 years) follow-up was available for 27 (79 percent). Twenty-three (85 percent) of these patients underwent microvascular muscle transplantation (gracilis or latissimus dorsi), and four underwent local muscle flaps (gastrocnemius or soleus) for immediate wound coverage. Twenty-four patients (89 percent) healed and were without recurrence over long-term (greater than 5 years, mean 7.4 years) follow-up. Of the three with recurrence, two were cured (greater than 5 years follow-up) after additional muscle-flap procedures. Thus the overall success rate was 96 percent, with a minimum 5-year follow-up. Guidelines for muscle-flap selection and treatment techniques in current use are presented. Debridement and immediate muscle-flap coverage provide effective, single-stage treatment of chronic osteomyelitic wounds and allow antibiotics to be restricted to short-term use. Furthermore, muscle flaps covered with skin grafts provide durable coverage while allowing subsequent ancillary procedures (i.e., bone grafts) to be performed under the flaps.