It is known from the literature that α-olefins polymerize to liquid hydrocarbons in the presence of a whole series of complex organometallic catalysts (NiCl 2 and CoCl 2 with AIR 3). In the presence of alkylaluminiums alone at 200° and a pressure of 100 atm, ethylene forms a wide range of liquid hydrocarbons of extremely diverse structures. Under the same conditions, propylene mainly dimerizes [1–3]. There are no data whatever in the literature of the kinetics of the polymerization of propylene on the catalytic system TiCl 4+Al( iso-C 4H 9) 2Cl and on the composition and structure of the polymerization products. It is known only that ethylene polymerizes on this system to form a plastic with an intrinsic viscosity of 2–3 [4]. The object of the present work was to study the kinetics of the polymerization of propylene on this system and to analyse the reaction products. We have established that at 80–100° with this system propylene polymerizes to give liquid products.