Superchargers are engine driven positive displacement devices which increase the air mass flow into the engine, thereby leading to better combustion. This gives an advantage of extracting more power from the same engine, thereby reducing emissions and achieving a better fuel economy. With emission norms getting more and more stringent, the need for boosting engine intake air becomes very important. The roots type supercharger works on the principle of backflow compression, where in, air in a plenum at higher constant pressure leaks into chambers which discharge air into this plenum. This discharge of air from chambers is effected by rotating members called lobes in a close toleranced housing, thereby forming chambers. Since the rotors rotate at high speeds, safe clearances must be maintained between housing and rotors. These clearances result in axial ad radial leakage paths between chambers which lead to a reduction in mass flow rate for the said pressure ratio. A 1-dimensional model of supercharger gives flexibility of choosing the right aspect ratio (length to the diameter of the rotor), deciding on the clearances (a trade-off between volumetric efficiency and manufacturing capabilities) and arriving at the inlet and discharge port dimensions. The dependency of the above parameters on mass flow rate of air and volumetric efficiency of the supercharger can be studied in good depth with a simplified one dimensional model This paper aims to present a one dimensional model of roots type twin rotor (each 3 lobed) supercharger, using pre-modeled library components on GT-Suite. The model also includes the inlet and outlet piping to replicate actual test bench setup. This model has been validated with the test setup for different speeds and pressure ratios and is found to be accurate to the tune of min. 93% on mass flow and min. 97% on discharge temperatures. This model further assists in developing a compressor map which helps in matching the supercharger to the engine requirements.