Hydrocarbon-type fractions (saturates, aromatics, polynuclear aromatics, and polar compounds) from heavy crude oils and synthetic fuels were separated by thin layer chromatography (TLC) on chromarods, using an Iatroscan TH-10 analyzer. The best results were obtained on a silica gel chromarod when n-hexane, 10 percent benzene in n-hexane, and 5 percent ethyl acetate in benzene were used as developing solvent. A complete analysis of six samples takes 60 min and requires only 60 mg of sample. Separation was applied to pure hydrocarbon mixtures as well as hydrocarbon-type concentrates isolated from Athabasca bitumen by liquid chromatography. The method is applicable to middle distillates, b.p. 200 to 35O°C, as well as to deasphaltened fractions (malthenes) boiling higher than 350°C Seven samples of malthenes (pentane-solubles) were analyzed by this method.