Asphaltenes precipitated by the use of pentane, heptane and decane solvents from Saudi Arabian Light (AL) and Saudi Arabian Heavy (AH) crude oils 370°C + residua have been investigated by thermal gravimetric analysis and pyrolysis - gas chromatographic analysis at 350°C and 520°C. Gas chromatographic analysis of the gases evolved during pyrolysis has shown that CO, CO2and CH4constitute the major portion of the gases evolved at 350°C from pentane and heptane asphaltenes of AH residue and from pentane asphaltenes of AL residue. Whereas gases evolved from decane asphaltenes are dominated by CO2and C2-C4hydrocarbon gases. At 520°C, hydrogen and methane represent 56-80 vol %of the gases evolved from all the four asphaltenes. The amounts of C1-C4hydrocarbon gases increased with an increase in the carbon number of the precipitating solvent at 350°C and decreased at 520°C. The presence of up to C36normal alkane hydrocarbon has been indicated in the maltenes produced from these asphaltenes. The loss of nitrogen from AH asphaltenes during pyrolysis remained low (1-6 wt %), whereas the losses of oxygen and sulphur ranged from 58 to 74 wt % and 10 to 29 wt %, respectively.