In this investigation, Computational Fluid Dynamics (CFD) is used to numerically simulate vehicle defroster performance. The general-purpose CFD package FLUENT/UNS is used to perform the numerical simulation. It is difficult to accurately model the actual flow and conjugate heat transfer phenomena in the vicinity of the windshield because of the complexity of the geometry and flow conditions, including the correct turbulence model. The objectives of this study are to quantify the velocity field in the vicinity of the windshield due to defroster jet flow, predict the windshield defrost pattern, and validate the use of CFD simulation in the engineering design and development process. This paper identifies the computational methodology and presents the simulation results. It also contains the hot-wire validation measurements for the velocity field as well as the cold room testing of the defroster performance.