Estonian shale oil obtained at shale industrial retorting contains up to 26 % phenols. Phenols are highly marketable and could be considered compounds already upgraded on retorting. Production practice includes washing out phenols with water and sodium hydroxide. The question is whether to prefer the hydrogenation of total or dephenolated oil. The aim of this work was to elucidate both the changes in the composition of phenols occuring during their hydrogenization and distribution of products, to solve the problem of preference stated above -i.e. to obtain the phenols as washed-out final products or additionally decompose them in the composition of fetal oil to get constituents of the upgraded oil.