During a prospective randomized trial, 50 geriatric patients underwent surgery for a fractured femoral neck. The perioperative circulatory and respiratory effects of anesthesia with enflurane or balanced anesthesia with enflurane and fentanyl were compared. We were particularly looking for postoperative respiratory depression after a standard dose of fentanyl given during balanced anesthesia. Method. In 25 patients anesthesia was induced with 0.2 mg/kg etomidate and 1 mg/kg succinylcholine and maintained with 0.15 mg/kg alcuronium and enflurane. Twenty-five patients received a additional dose of 5 micrograms/kg fentanyl divided into 0.1 mg/kg 2 min before endotracheal intubation and the remainder 5 min before the start of surgery. Systolic and diastolic arterial pressures, heart rate, central venous pressure, hemoglobin, hematocrit, and electrolytes were measured and arterial blood gases were analyzed. Results. There was no important difference between the two methods: during careful use of both techniques circulation remained stable. No marked postoperative respiratory depression occurred even after 5 micrograms/kg fentanyl. Conclusions. Both anesthetic procedures are suitable for hip surgery in elderly patients. In the early postoperative period geriatric patients should be observed carefully in the recovery room for at least 2 h. In some patients--especially if fentanyl is used intraoperatively--this time must be prolonged.