Abstarct: In this thesis, an observer-baxsed adaptive controller is proposed to regulate the blood glucose level of type 1 diabetic patients. In present work, a nonlinear Bergman minimal model (BMM) is considered for mathematically model type one diabetic patient. Firstly, the equations of BMM is transformed to affine form and then an adaptive observer is proposed to estimate both the state variables and the system parameters simultaneously. Furthermore, an adaptive feedback control rule baxsed on proposed observer are presented to bring back the blood glucose level to its safe range (i.e., 70 – 180 mg/dl). The proposed method overall stability is stablished using Lyapunov theory. To verify the effectiveness of the proposed approach in tracking the desired blood glucose, simulation results have been performed using MATLAB/Simulixnk. The simulation results demonstrate that the proposed method is extremely robust to parametric uncertainty as well as meal disturbance.