Two different types of scrap tires, passenger car tire (PCT) and truck tire (TT) with waste lubricant oil (WLO) were copyrolyzed in a fixed bed reactor at the temperatures of 550, 650 and 800 degrees C under nitrogen atmosphere. Copyrolysis products were investigated comparatively. The gaseous products were analyzed by GC-TCD. The psychical and chemical properties of copyrolysis oils were characterized by means of ASTM methods, GC-FID, GC-MS, and H-1 NMR. In addition, boiling point distributions of hydrocarbons in copyrolysis oils were determined by using simulated distillation curves in comparison with commercial diesel. An increase in the temperature had no effect on the product distributions of copyrolysis and the composition of copyrolysis oils. However, the types of scrap tires strongly effected the product distributions and compositions of copyrolysis oils. Copyrolysis of PCT/WLO produced less amount of liquid and more amount of solid residue than that of copyrolysis of TT/WLO. However, the naphtha and aromatic content in oils from copyrolysis of PCT/WLO was found more than that of TT/WLO. The amount of aromatic content in copyrolysis oils found to be less than that of scrap tire derived oils. By comparing the copyrolysis oils with commercial diesel, copyrolysis oils contained lighter fraction than that of commercial diesel whereas the specific gravities and viscosities of copyrolysis oils were higher than that of commercial diesel. (c) 2005 Elsevier B.V. All rights reserved.