Three titanium complexes having phenoxy-imine chelate ligands: bis[N-(3,5-di-tert- - butylsalicylidene)anilinato]titanium(IV) dichloride (complex I), bis[N-(3,5-di-tert-butylsalicylidene)- - 1-naphtylaminato]titanium(IV) dichloride (complex II) and bis[N-(salicylidene)-1-naphtylaminato]titanium(IV) dichloride (complex III) were synthesized and used as ethylene polymerization catalysts in conjunction with various organoaluminum compounds. It was found that both ligand structure and activator type (MAO, Et 3 Al, Et 2 AlCl, EtAlCl 2 ) had great impacts on activity of complexes investigated. On the other hand, the type of alkylaluminum compound, much more than the structure of the complex determines the properties of products of the polymerization leading to high molecular weight polyethylene or low molecular weight polyethylene and oligomers.