From 1979 to 1990 we treated 20 patients with large bone defects or established nonunion of the femur by vascularised fibular grafts. There were 18 men and two women with an average age at operation of 36.6 years (16 to 69). Ten patients had infected nonunion, three had post-traumatic nonunion or a bone defect without infection, four had a defect after tumour resection, and three had other lesions. The mean length of the fibular grafts was 18.1 cm. Postoperative circulatory disturbances needed revision surgery in five patients, including three with circulatory problems in the monitoring flap, but not at their anastomoses. The outcome was successful in 19 of the 20 patients with bone union at means of 6.1 months at the proximal site and 6.6 months at the distal site. Three patients had fractures of the fibular grafts but all these united in two to three months after cast immobilisation.