Reamed interlocking nail through the piriformis fossa remains the golden standard for treatment of femoral shaft fracture. Fracture healing rates are 95–99%, and infection rates less than 1% (Clawson et al. in J Bone Joint Surg (Am) 53:681–692, 1971; Winquist et al. in J Bone Joint Surg (Am) 66:529–539, 1984; Brumback et al. in J Bone Joint Surg (Am) 70:1453–1462, 1988). Previous reports recognize avascular necrosis of the femoral head as a complication of antegrade interlocking nail in the adolescent (Beaty et al. in J Pediatr Orthop 14:178–183, 1994; Mileski et al. in J Bone Joint Surg (Am) 76:1706–1708, 1994; O'Malley et al. in J Pediatr Orthop 15:21–23, 1995; Buckaloo et al. in J Southern Orthop Assoc 6(2):97–100, 1997). This report describes a male adult who developed avascular necrosis of the femoral head after an open antegrade interlocking nail of a proximal third femoral shaft fracture. To our knowledge, there is no similar report in the English medical literature.