Although many retorts for processing oil shale have been in operation at one time or another, few have been economical from the standpoint of heat requirements. Since a large portion of the heat required to retort oil shale is used in bringing the shale up to retorting temperature, preheating the shale would materially decrease the amount of heat that must be supplied by the retort and also make use of what would be possibly wasted heat. In order for such preheating to be feasible, it should not adversely affect either the yield or quality of oil. This study was undertaken to determine the effects of preheating an oil yield, and was very preliminary in nature. The method used in the investigation consisted of comparing the oil yield obtained by retorting oil shale in an oxidizing atmosphere with that obtained by retorting a similar shale in an inert atmosphere.