The demand for natural gas is increasing since recent climate change. Natural gas is considered an abundant energy source with low greenhouse-gas emissions. A natural gas engine usually operates in lean-burn mode to gain the advantage of high thermal efficiency and low nitrogen oxides emission. A problem typically associated with natural gas combustion in lean mode is poor ignitability. The objective of this study is to improve ignitability of lean natural gas combustion using gas-jet ignition method. Several experiments were done using a confined volume chamber apparatus. Images of the combustion flame were captured using a high speed camera, and hydrocarbon emissions were measured. The result showed that the gas-jet ignition method is effective in improving ignitability of lean natural gas mixture. An addition of 30% hydrogen gas to the natural gas fuel improves both the ignitability and further flame propagation, thus lowering the hydrocarbon emission.