The Response Surface Methodology (RSM) was employed to investigate the effects of pH and current density on the removal of cadmium, copper and zinc in a artificial wastewater with a large COD by electrocoagulation technique. Six iron electrodes were used in a 2 l reactor with agitation. A regulated AC/DC power supply was used maintained a constant voltage/current. The initial samples were prepared with a COD of 10000 mg/l, oils and grease of 2000 mg/l, and heavy metals concentration of 250 mg/l. The initial and final concentrations were measured by atomic absorption spectrometer. Removal of more than 99% was obtained during the process for 60 minutes of application time. The conditions for optimal removal were at pH of 8 and a intensity of 3A for cadmium, pH of 7.02 and Intensity of 3 A for copper and zinc.