This paper presents an overview on the development of hydrogen fueled internal combustion engines and ties together the recent efforts with the past achievements in this field. The causes of various undesirable combustion phenomena such as backfire, pre-ignition, knocking and rapid rate of pressure rise which have historically bothered the hydrogen engine researchers have been put forward and ways adopted to eliminate them have been discussed. A futuristic outlook of hydrogen utilization in engines is presented. © 1990.