The effect of seawater (SW) conductivity on the treatment of domestic solid waste leachates (DSWL) and hazardous solid waste leachates (HSWL) by means of EC was investigated. Seawater, which is a strong electrolyte with a rich content of ions, has been fed together with the leachates to the reactors with Fe and Al electrodes. In the experiments, the treatment was performed by mixing leachate (DSWL and HSWL) with seawater in the proportions of 1:1 and 1:3. The efficiency of the process was determined by observing such parameters of suspended solids as phosphate, sulphate, color and turbidity. It was determined that the removal efficiencies related to the amount of seawater added, increase for all parameters except sulphate ions removal. Obtained data showed the best removal efficiency for Fe and Al electrodes ranging from 67 % to 100 % in the phosphate content, color and turbidity. For suspended solids and sulfate ions, the removal efficiencies vary in the range of 50-70 %.