This paper presents an intelligent controller for voltage tracking control of DC-DC boost converters. The control law is a brain emotional learning based intelligent controller (BELBIC). It uses the inductor current error and the output voltage error to calculate the desired duty cycle. The controller design is free from the mathematical model of the system. In fact, all of the system dynamics and parameters are considered as uncertainty. In comparison with other intelligent controllers such as fuzzy systems and neural networks, BELBIC controllers are simpler, since they have fewer parameters. As a result, the tuning procedure of BELBIC controllers is simpler. Simulation results show the satisfactory performance of this controller in rejecting the external disturbances caused by the sudden changes in the load resistance and the input voltage.