Trickle bed reactors are widely used in petroleum refining industry for various hydro-treating purposes to remove sulfur primarily from light and middle distillates. In last few years due to stringent environmental norms on emission, importance of rigorous design of trickle bed reactor has drawn much research attention. Although the technology of trickle bed reactor design is well established, it has been essentially based on heuristics. With availability of more computational power, computational fluid dynamics (CFD) appears to be an essential tool to understand effect of flow on transport phenomena which directly govern the design. A complete analysis of trickle bed reactor design requires modeling of hydrodynamics, reactor internals and catalyst bed. All these three aspects have been incorporated in this work to build up the CFD models. This analysis should help to shed some light on understanding various aspects of CFD modeling of trickle bed reactor and should be helpful for professionals engaged in research or design of trickle bed reactor using CFD.