Electrochemical methods in combination with a chemical process enable the treatment of residuary water containing hydrocarbons. Electroflotation is adequate for the separation of oil from oily wastewater. However, the main disadvantage of this method is the oil concentration limitation. Flocculation plays an important role in the improvement of this process due to its ability to remove organocolloids. In this study the evaluation of the most important operating parameters was examined. An experimental design was applied in order to estimate the effect of operating conditions on the performance of the coupling of flocculation with electroflotation by measuring chemical oxygen demand, turbidity and conductivity. Three various flocculants were considered. The efficiency of oil separation reached 99% for a concentrated emulsion of 4% (wt.) at optimum conditions and at an optimum concentration of flocculant agents.