The effect of changes in some of the experimental parameters on the oil yield has been determined in a laboratory scale reactor heated by an external electrical heater: Five categories of particle sites of oil shalt samples from two deposits in Jordan were pyrolysed by employing a fixed bed retorting system. The reactor and the oil shale sample were heated at a constant rate, and nitrogen gas was used to purge the sample, continuously,, in order to remove the pyrolysis products from the reactor as well as to reduce secondary reactions. The liquid products were condensed and collected in a series of cold glass-traps and the off-gases analysed for their hydrocarbon and non-hydrocarbon species. Subsequent experiments were carried out employing a thermogravimetric ic analyser using only the four smallest particle sites under similar conditions as applied to the fixed bed retort The activation energy was determined using the integral method. The pyrolysis of the investigated shales was found to comply with first-order kinetics within the limits of experimental error Increasing the particle site resulted in a slight rise in the liquid oil yield, but simultaneously the total gaseous production was decreased The highest oil yield was obtained at a temperature of 480 (+/-30) degrees C. Results obtained from this slurry agree with those for other grades of oil shales extracted from various deposits world-wide.