Results of a study on the liquid-phase oxidation of naphthenic hydrocarbons from the 200-300degreesC fraction of Senomanian condensate at temperatures of 120-140degreesC in the presence of an equimolar mixture of manganese and potassium stearates (1.02 x 10(-2) mol/l) are presented. From the oxygenates obtained, naphthenic acids with an acid number of up to 190 mg KOH were isolated in a 25% yield. The presence of functional,groups was confirmed by IR data.