In this century, it is believed that the crude oil and petroleum products will become scarce and expensive. Moreover pollution from transport vehicles poses a threat to the environment. To overcome these problems, alternative fuels are being sought after. The following paper discusses the reliability of gaseous alternative fuels best suited for compression ignition (CI) engines. The use of Hydrogen, Biogas, CNG, LPG, and Syngas in CI engines is being reviewed. Among the renewable energy sources, gaseous alternate fuels offer a promising opportunity for sustainable development in the energy and transportation sectors. The review work also emphasizes the use of syngas as an environmental friendly future fuel in CI engine and HCCI engine in comparison with other gaseous fuels. © 2016, International Journal of Pharmacy and Technology. All Rights Reserved.