BACKGROUND The management of infection after intramedullary nailing of the femoral shaft fracture remains a challenge to orthopedic surgeons. The dilemma confronting surgeons concerns the removal or retention of the nail in the presence of infection. METHODS The authors treated 23 infections after intramedullary nailing for femoral fractures. All fractures were unhealed at presentation. All patients were followed for at least 1 year after the infection. Acute infection occurred in 13 patients, subacute infection in 5, and chronic infection in 5. The patients were divided into two groups on the basis of the method of the initial treatment. In group I (12 patients), the intramedullary nails were retained, and there were 11 men and 1 woman, with an average age of 36 years (range, 15-55 years). In group II (11 patients), the nails were removed at the time of debridement and the fractures were stabilized with external fixation, and there were nine men and two women, with an average age of 44 years (range, 25-69 years). RESULTS In group I, all fractures healed within an average period of 9 months (range, 5-15 months) after surgical debridement. There was no recurrence of infection at an average follow-up of 25 months (range, 12-76 months). In group II, seven fractures healed within an average of 10 months (range, 4-24 months) after treatment. At an average follow-up of 33.8 months (range, 12-79 months), infected nonunion was noted in two patients. More complications occurred in group II patients in comparison with group I patients. Limited range of motion of the knee joint was usually encountered if a fracture was stabilized with external fixation for a prolonged period of time. CONCLUSIONS Retention of the intramedullary nail is performed if the fixation is stable and the infection is under control. External fixation is most suitable for uncontrollable osteomyelitis or infected nonunion. Staged bone grafting is usually necessary when a bone defect is present.