Users of fossil fuels are facing a range of challenges such aslong-term rising demand, climate concerns due to emission ofgreenhouse gases, ecological pollution, finite reserves and price fluctuations. Diesel fuel is similarly affected, though with its own subset of issues. Studies suggest that diesel fuel characteristics are affected by addition of nanoparticles. In this research, carbon nanotubes (CNTs) were blended with pure diesel as an additive at concentrations of 30, 60, and 90 ppm to assess the emission and performance characteristics of a single-cylinder compression combustion engine. The considered emission contents included CO, CO2, HC, and NO produced by an engine at 50% and 100% loads, at 1800, 2300, and 2800 rpm. Addition of CNTs to the diesel fuel considerably reduced the emission of CO, CO2, HC, and NO compared to additive-free diesel fuel. Furthermore, with the addition of carbon nanotubes, the Exhaust Gas Temperature (EGT) and the Brake Specific Fuel Consumption (BSFC) decreased, while the power and Brake Thermal Efficiency (BTE) increased at all loads and speeds of the engine.