A multilevel DC-DC boost converter was proposed recently. It is able to provide very high voltage gain with small duty-ratio, low switch component stress and many other merits. However, few controllers have been proposed for this converter. In this paper, a sliding-mode controller for regulating this dc-dc multilevel boost converter is proposed. The sliding surface is constructed using the inductor current error and the integral of the output voltage error. Based on a general reduced-order state-space model of this converter, the controller design and the stability analysis of the sliding-mode controlled converter system are carried out. Experimental results for a 3× dc-dc multilevel boost converter show the validity and feasibility of the proposed sliding-mode controller under various converter operation conditions.