Abstract: Electrochemical reduction of europium cryptatcs Eu(NO₃)₃(2,2) and Eu2(NO₃)₆(2,2,2) were investigated by means of cyclic voltametry in dichloro-methane, dichloroethane, acetonitrile, acetone, benzonitrile, pyridine, dimcthyl-formamidc and dimethyl sulioxide, The halfwave potentials of redox reaction and electron-transfer rate constants were determined, and the effects of solvent and supporting electrolyte on E_1/2and k_swere discussed.