A study has been made of the bulk conversion of 1-decene on complex catalysts containing Zr(OC3H7)(4) and Zr(OCO-iso-C3H7)(4) and Al(C2H5)(3), (C2H5)(2)AlCl or (C2H5)(1.5)AlCl1.5 at temperatures of 80-110 degrees C. It has been established that the total conversion of 1-decene under the action of the given catalysts depends on the nature of the organoaluminium cocatalyst and decreases in the order (C2H5)(1.5)AlCl1.5 > (C2H5)(2)AlCl > Al(C2H5)(3). The main products of conversions of 1-decene are 2-ethyl-1-decene, dimers and trimers of 1-decene, and also 2-decene. The yield of 2-ethyl-1-decene increases with an increasing Al/Zr molar ratio and reaches 20 mole/mole zirconium compound in the catalyst. The probable mechanism of the conversions occurring is proposed.