The influence of thiourea (TU) and dialkylderivatives of thiourea: N,N-dimethyl-(DMTU), N,N-diethyl-(DETU) and N,N-dibuthyl- thiourea-(DBTU) on the electroreduction of Zn (II) was studied in water + ethanol 98% vol. + NaClO4 mixtures. The results obtained are discussed taking into account TU, DMTU, DETU, DBTU adsorption on the electrode surface as well as the possibility of formation of an active complex by a metal ion with TU and dialkylderivatives. The results suggest that the complex structure plays the dominant role of the electrode process acceleration