Thermal pyrolysis of the Cassia siamea seed was carried out in a fixed bed reactor in the temperature range of 450 degrees C and 575 degrees C at a heating rate of 50 degrees C min(-1). The reactor was maintained inert using nitrogen gas at a flow rate of 40 mL min(-1). It was observed that the highest yield of pyrolytic liquid was 50.21% obtained at 550 degrees C which includes 39.86 wt% of organic liquid (oil) and 10.35 wt% of aqueous liquid. The fuel properties of pyrolytic oil confirmed that the oil was slightly basic with a pH of 8.75, having viscosity and calorific value of about 373 cSt and 30.18 MJ kg(-1) respectively. The GC-MS based composition analysis quantified the occurrence of many valuable bio-chemicals such as heptadecanenitrile, 1,2-benzene dicarboxylic acid, butyl octyl ester, phenol, p-cresol as major compounds.