Combustion and emission characteristics were investigated in LPG engine with hydrogen addition. At λ=1.7 and 2.0, high combustion stability was found with hydrogen even though its change was small at λ=1.0 and 1.3. Stable operation of the engine was presented even at λ=2.0, if the amount of hydrogen gas was near 63% volume fraction (15% of total energy). High in-cylinder temperature due to hydrogen combustion resulted in further heat loss to surroundings. Except for λ=1.0, with larger blending of hydrogen, CO was reduced significantly but it was not the case at the leaner region. Nitric oxides(NOx) was increased slightly with hydrogen at λ=1.0 and 1.3. However, when λ>1.3, its relative amount of emission was low. NOx was continuously decreased with hydrogen. However, at λ=2.0 NOx was lowered to a factor of 100 at λ=1.0. THC emission was significantly increased as air/fuel ratio close to leaner region due to misfire and partial burn.