The consumption of fossil fuels spawns environmental considerations in addition to issues of energy demand, national security and resource availability. At global level, scientists warn that the combustion of fossil fuels is significantly changing the world's climate system. Local or regional concerns include smog, acid rain, and health implications of urban air pollution. Due to stringent emission norms and depletion of petroleum resources there has been a continuous effort to use alternative fuels such as hydrogen. It has its own benefits and limitations if it is used in conjunction with conventional fuel in diesel engine. The purpose of this article was to investigate the effect of hydrogen addition on performance and exhaust gas emission of stationary diesel engine. In this study, hydrogen was used as secondary fuel in a single cylinder 406 c.c. diesel engine. The hydrogen was injected through intake manifold and diesel was injected directly inside the combustion chamber. Series of experiments were conducted and it can be seen the effect of hydrogen addition in the increase of peak pressure from 5 bar to a maximum 21 bar, IMEP from 1.0 to 1.7 bar , indicated power from 4%-16%. There were also increases in NOx and CO emissions from 48-197 ppm and 423-758 ppm, respectively. Hydrogen addition causes increase in exhaust gas temperature from 3.1% to 10.2% particularly at 2500 rpm and reduction in O 2 emissions from 3.9% to 7.6% (by volume) throughout all engine speeds.