Hydrogenation offers one means of upgrading shale oil or shale-oil fractions for use in motor fuel production. Of particular interest in this field is the hydrogenation of coker distillates and shale naphthas produced by thermal cracking. The purpose of this study was to determine the effects of variations in operating conditions upon yield, hydrogen consumption and product quality. Based on the results of these surveys, optimum ranges of operating conditions were determined for each charge stock and catalyst life and heat of hydrogenation determined within these ranges.