This project studies a robust control for regulating a boost converter capacitor output voltage. The boost converter is inherently a highly nonlinear system that displays interconnected state variables and system parameter variations due to load change with input disturbances. Therefore, a robust control scheme is required to cope with these characteristics. The main objective of controlling the capacitor output voltage is to keep the output voltage constant under input voltage variations with fast response, and little overshoot and ripples. To satisfy this objective, a robust control with time-delay concept is introduced. The control utilizes time-delayed switching input to the converter, as well as output current and voltage variables, to replace the unknown dynamics and disturbance. To prove the effectiveness of the algorithm, two operating point variations are considered: variations in source voltage, and changes in output load.