Variable rate pump for insulin delivery has as its pumping unit a syringe. A motor is connected to advance the syringe and electric signal pulses are produced during syringe advance. A control system permits selection of the interval between command pulses to maintain the desired base insulin delivery rate. A separate circuit drives the motor and syringe to deliver a predetermined bolus of insulin. Alarm circuits are connected to monitor the various system requirements and signal when they are not fulfilled.