The thermal decomposition of dichloromethane extracted Athabasca tar sand bitumen and Athabasca tar sand itself was studied in a stream of 30 ml/min helium at temperatures in the range 350-550 degrees C, The volatile products obtained were analyzed by gas chromatography. It was observed that the products were mostly comprised of n-paraffins. Elemental analysis of the residues obtained from thermal decomposition indicated that decomposition was complete between 450 degrees C and 500 degrees C. The catalytic effect of sand, obtained by dichloromethane extraction of Athabasca tar sand, on the thermal decomposition of hexane and hexene was investigated at several temperatures, It was observed that the extracted sand had no catalytic effect on the decomposition of hexane and hexene up to 450 degrees C, but catalyzed the thermal decomposition at 500 degrees C or higher, The catalytic effect of the sand was fairly significant in the case of hexene. The products obtained from hexene decomposition were comprised of more than C-6 hydrocarbons. Hexane decomposition products contained C-6 or less than C-6 hydrocarbons.