With great advancements in computer hardware development, application of Computational Fluid Dynamics (CFD) in Wind Engineering has become a feasible option to study the wind effects on buildings and structures. In the present study, numerical simulations have been carried out on a 1:2:5 rectangular building model (0.1 m x 0.2 m in plan and 0.5 m of height) using CFD software FLUENT 6.3. For the wind direction normal to shorter face of the building, uniform wind speed of 10 m/s is chosen with turbulence intensity of 0.2% (for uniform smooth flow condition) at the inlet boundary. Two types of turbulence models, viz. (i) Realizable k-e turbulence model, which is single scale type turbulence model and (ii) DES turbulence model with Realizable k-e option, which is multi-scale type hybrid turbulence model have been considered. The evaluated mean overall drag coefficient, standard deviation overall lift coefficient and Strouhal number are compared with the experimental values reported in the literature for the assessment of performance of these two turbulence models. Keywords: RANS, DES, Pressure Coefficients, Force Coefficients, Rectangular Building, Uniform Flow.