Temperature-programmed co-pyrolysis of Turkish oil shales with atactic polypropylene (APP) was investigated. The: aim of this research was to determine the volatile product distribution and product evolution rate of co-processing of oil shale with APP. A series co-pyrolysis operation was performed with oil shale and APP using a 1:3, 1:1; 3:1 total carbon ratio of oil shale to, plastic. A fixed bed reactor was used to pyrolyze a small sample of an oil; shale and APP mixture under an inert gas flow (argon). A special sampling technique was used for collecting organic products; eluted from the reactor at different temperature and time intervals.-The co-pyrolysis products were analyzed by capillary gas chromatography and the-total product evolution rate was investigated as a function of temperature and time. n-Paraffins and 1-olefins in aliphatic fractions of pyrolysis products were classified as a carbon number. In addition, the recovery of total organic carbon as an organic volatile product was determined. The assessments were based;on incorporating the results on temperature-programmed pyrolysis of oil shale(1,2) and APP. The effect of co-processing of oil shale with APP was determined by calculating the difference between the experimental and the hypothetical mean value of conversion of total organic carbon into volatile products. The effect of kerogen type of oil shale on co-pyrolysis operation was also investigated. Conversion into volatile hydrocarbons was found higher with-an increasing APP ratio in the oil shale-APP systems while C16+ hydrocarbons and the amount of coke deposit were lower in the presence of APP.