Type 1 diabetes is characterized by the destruction of the only insulin producing cells in the body. The typical course of action consists of daily insulin injections or an insulin pump. Assuming available methods for online monitoring of glucose concentrations, feedback control can be applied to this problem to improve regulation of glucose concentrations. A control algorithm is presented for feedback control of glucose levels in Type 1 patients. The control problem may be viewed as asymmetric, with negative variation from normal values treated with a more aggressive response than positive deviation. A simple asymmetric proportional-integral ( PI) controller is presented where controller parameters vary depending on the sign of the current error value. Optimal closed-loop tuning parameters for the asymmetric control system are determined using local search methods. The asymmetric control system is then considered for robustness analysis using standard techniques from linear systems theory.