Recent studies discussing applications of internal combustion engines running with different fuel types attract more attention of researchers nowadays. However environmental and enviroeconomic aspects of these fuels are as significant as employability and performance effect of them. So it is required to evaluate use of different fuels in internal combustion engines environmentally and enviroeconomically. In this paper an LPG fueled 2-cylinder SI engine was evaluated environmentally and enviroeconomically at partial load for the first time. Within this scope the engine has been firstly examined experimentally and then environmental and enviroeconomic parameters are calculated. Obtained emissions data in the end of the experiments are used to reveal environmental impact of the engine. An approach for environmental cost determination is also applied using emissions data, carbon pricing and engine power. In the end of the study variation of emissions, environmental impact and environmental cost with engine speed are revealed. The maximum environmental damage and environmental cost of the examined engine are determined to be 9.365 tCO(2).year(-1) and 77.539 and USD.year(-1) respectively while the engine power and specific fuel consumption are 5.604 kW and 311.877 g.kWh(-1) at 4000 rpm value of engine speed.