Biogas is a renewable energy which can be used for fuel in the internal combustion engine and produce electricity by using a generator. On a small scale, electricity generation from biogas is important and attractive for special purposes especially for the areas which are not connected to the main electricity network or which are plenty of sources of biomass waste. Therefore, the purpose of this study is to investigate the performance and emissions of the internal combustion engine using the biogas fuel. The study was conducted by a simulation using ASPEN HYSYS and by experiment. The biogas pressure was varied from 0 to 4 barg. The results show that the highest power and efficiency were obtained at 700 W and 14.2%, respectively. The use of pressurized biogas can increase efficiency by 1%. Low CO and HC emissions and high CO2 emissions indicate that combustion occurs completely.