Climate change and global warming caused by air pollution have become one of the most important problems of our day. Diesel engines, which cause high levels of pollutant emissions, mainly NOx and PM, are the main sources of air pollution. Many different technologies have been developed to reduce pollutant emissions from diesel engines. DOC (Diesel Oxidation Catalyst) and SCR (Selective Catalytic Reduction) are among the most widely used technologies. In this study, DOC and SCR technologies are used to reduce the pollutant emissions of a single cylinder diesel engine. As a result of the DOC and SCR catalysts placed at the exhaust outlet, significant reductions in pollutant emission values have been achieved.