A new spring-driven syringe pump (Springfusor 10, Go Medical Industries, Subiaco, W.A.) was evaluated for infusion of muscle relaxants in 50 surgical cases. After an initial bolus dose, atracurium was given at a rate of 25 to 37.5 mg/hour and vecuronium at a rate of 4 to 6 mg/hour. The mean infusion rate was found to be 4% above the nominal rate of 5 ml/hour and the accuracy in all cases was within +/- 20%. The Springfusor was found to be rugged, cheap and easy to use. It lacks dose flexibility but is suitable for continuous background infusion of muscle relaxants during surgery.