New catalytic systems based on nickelocene were used as initiators in polymerization of ethyl acetate carbene derived from ethyl diazoacetate. Nickelocene itself and nickelocene activated with n-butyllithium or diphenylmethyllithium led to the formation of oligomers with average molecular weight about 800 Da. eta(5)-Cyclopentadienyl(1,3-dially1-imidazolin-2-ylidene)nickel bromide activated with an excess of methylalumoxane gave ethyl acetate carbene polymer with average molecular weight 21,800 Da. MALDITOF spectra indicate coordination-insertion mechanism of polymerization in all catalytic systems applied. (C) 2014 Elsevier B.V. All rights reserved.