Surgery for humeral shaft fractures. A series of 78 operative treated humeral shaft fractures was studied retrospectively. Sixteen times we found a radial nerve palsy, preoperatively. In this group we evaluated the type of fracture, the operation indication, the time of treatment and the postoperative recovery of the radial nerve palsy. Fourteen times we did an early exploration. The indication to operate was 9 times the conducting polytrauma, 5 times the radial nerve palsy itself and 2 times a pseudarthrosis. In 13 of the 16 patients nerve function recovered either clinically and/or electromyographically. This study confirms that radial nerve palsy is found especially in fractures located at the junction of the middle and the lower third of the humeral shaft. Because we found nearly always a macroscopically lesion of the nerve in this type of fracture, we recommend an early exploration in spiroid fractures at that junction. For the same reason we advise an early exploration in cases of secondary radial nerve palsy. If no other indication to operate occurs, we accept a conservative treatment of the humeral fracture with radial palsy.