Gerotor pump is a positive displacement pump unit which is widely used for lubrication in on-road and off-road engine applications. This paper is focused on Gerotor pump design competency established at ARAI comprising of design of inner and outer rotors, suction & delivery ports, optimizing inlet and outlet diameters & its position, development of methodology to calculate oil flow rate, volumetric efficiency, mechanical efficiency & slippage. The finalization of design is followed by CFD of Gerotor pump to optimize the pressure and flow pulsation.A trochoidal profile is used to design the inner and outer rotors and its conjugate profile are realized by a set of equations using a method based on the theory of gearing. Suction and delivery port is analytically designed based on the same design parameters of the trochoidal profile. The variation in pressure pulsation due to the rotor geometry of the Gerotor pump is reduced by the introduction of metered porting considering the location and groove width and depth of the ports. The critical design parameters and port shapes, which affects the flow ripples and pressure pulsation, is identified and optimized using computational fluid dynamics. The manufacturing of pump is carried out and test results are compared with calculated oil flow requirement.A GUI based algorithm is developed in MATLAB environment for easy interface between user and calculation procedure. The output from the GUI is directly used for 3D Modeling of Oil pump.