The aim of this study was to investigate the predisposing factors, fracture location, treatment, and final outcome of femoral fractures after total hip arthroplasty (THA). From 1975 to 1983, 28 patients were seen with 29 fractures on the same side as the prosthesis. Most of the fractures were caused by minor trauma, and prior hip surgery was the most common predisposing factor. Two patients underwent early operation and six were treated with protected weight bearing. Twenty-one underwent initial skeletal traction, and 14 of these fractures united without further surgery. Six of the patients treated with initial skeletal traction were operated on early, mainly by osteosynthesis, due to poor fracture alignment. Three of these fractures united, but one subsequently required revision arthroplasty because of loosening of the femoral component. Two patients died and three had a permanent pseudarthrosis or a Girdlestone resection. Nineteen of the 21 fractures not operated on united and five of the eight operated united. The results indicate that when good fracture alignment is achieved with traction, union is not jeopardized by either the prosthesis or the cement.