The cis- and trans-potassium bis(oxalato)diaquochromates(III) have been studied towards their catalytic activity for the 2-chloroallyl alcohol oligomerization. The geometric isomerism effect on the oligomerization products under mild reaction conditions has been investigated. The molecular masses andtactic structures of obtained poly(2-chloroallyl alcohols) have been compared and analyzed. The mechanisms of oligomerization processes have been proposed. It has been proven that two studied complexes – cis-K[Cr(C2O4)2(OH2)22] and trans-K[Cr(C2O4)2(OH2) 2]·3H2O are highly active catalysts for the oligomerization of the beta-olefin derivative.