Vecuronium has been used for long surgical procedure by infusion or intermittent injection. However, such methods are not economical. It may be that the use of longer acting pancuronium followed by vecuronium would offer the advantages of economy and rapid recovery. The aim of this study was to investigate the duration of effect of vecuronium administered after pancuronium. Eighteen patient reguiring prolonged major surgery were given intravenous pancuronium 0.06 mg/ kg (ED95) after induction of anesthesia and a dose of pancuronium 0.06 mg/kg (Group I, nine patients) or vecuronium 0.01 mg/kg (Group II, nine patients) was given at the recovery of neuromuscular transmission where the response to the first stimulus (T1) was 25% of control response. As a result, the time of onset, recovery time of 25%, 50% and 75% of control response T1 and recovery index was to be shorter with vecuronium than with pancuronium. It is concluded that vecuronium administered at the end of surgery after pancuronium is effective for shorting the duration of recovery time.