PURPOSE: We wanted to evaluate the incidence and causative factors of avascular necrosis (AVN) of the femoral head after intertrochanteric fracture. MATERIALS AND METHODS: Between 1994 and 2004, 383 cases of intertrochanteric fractures were internally fixed. Among them, 287 cases were followed more than one year; these cases were the subjects of this review. The average follow-up period was 5.3 years (range: 1.6 to 9.3 years). We retrospectively reviewed the medical records and radiographs of the patients who developed AVN of the femoral head after sustaining intertrochanteric fracture. RESULTS: Seven patients (2.4%) were found to have developed AVN during the follow-up. No patients were thought to be at risk for nontraumatic osteonecrosis of the femoral head due to steroid or alcohol abuse. Good reduction and good implant position were achieved in all patients. The duration from injury to the development of AVN was from 1 year to 3.8 years. The possible etiologies were initial vigorous trauma to the head and iatrogenic damage of the blood supply during reduction and fixation of the fracture. CONCLUSION: The patients who sustained inter trochanteric fracture should be monitored for development of AVN, and especially if there was an unstable fracture.