Aerodynamics plays an important role in ground vehicle design and optimization. With the worldwide interest in saving energy, drag reduction is one area where aerodynamics can help. The aerodynamics of pickup trucks is studied. The main objective is to understand the effect of the box configuration on the generated aerodynamic drag. In addition to that, the flow structures around the vehicle are analyzed. The CFD simulations of a generic pickup truck are performed using STAR-CCM+ package developed by CD-adapco. Several commonly used pickup truck configurations are presented including open-box, a box with tonneau cover, and a pickup truck with a flat cap. It was found that the tonneau cover reduced the generated drag significantly. The cap cover generates slightly more drag than the open-box case.