Between 1976 and 1986 in our clinic 273 patients aged 3 to 93 years underwent operation of the femur shaft because of fracture. 79% had multiple injuries. 254 with 269 fractures survived. 52 out of them had open fractures. All operated fractures were analysed concerning fracture type, fracture localization and timing of operation. We saw 36 complications (13.4%), 13 bone infections (4.8) and 23 non-unions (8.6%). 40% of the patients were operated immediately, 23.4% within the first week. Early operation of closed fracture showed 11.5% complications, operation within the first week showed 14% complications, and delayed operation only 5.7% complications. We saw 7 infections (3.5%) and 20 non-unions (9.9%) after 202 fixations with AO-plates, and 2 infections (4.3%) and one non-union (2.2%) after 46 Küntscher-nailings. Multi-fragment fractures showed considerably more complications (15%) than other types. 23 fractures in the transition from the middle to the distal third had the highest complication rate (13% infections and 21% non-unions) followed by 115 fractures in middle part with 4.3% infections and 9.6% non-unions. Fixation of multiple-fragment fractures in the transition from the middle to the distal third with AO-plates had the worst rate of non-unions of all (4 out of 16). The reasons for the different complication rates are discussed. The striking increase of complications from proximal to distal shaft regions is explained by different blood flow alterations in femur diaphysis found in former experiments.