In the following an experimental investigation on a single-cylinder four-stroke spark ignition engine operating with gasoline was performed to study the effect of hydrogen addition to fuel on its performance and emissions. The hydrogen was inducted in the air inlet manifold with different volume ratios 24%, 26%, 27%, 28%, 29%, 31%, 35%, 37%, 49% of total intake volume. The combustion analysis was carried out for different percentage of hydrogen additions. The results show that due to the rapid rate of burning of gasoline-air mixture with the addition of hydrogen leads to increase in cylinder pressure. The engine test performance shows an improvement in thermal efficiency as well as reduction in brake specific fuel consumption. The emission analysis shows a reduction in unburned hydrocarbon (HC) and carbon monoxide (CO). Finally, using hydrogen blended with gasoline showed an improvement in efficiency and environmental benefit.