The wastewater treatment becomes more necessity. A cheap and more effectively methods for treating liquid waste before discharging it into any other water systems is required. A lot of wastewater technologies are known which include physicochemical treatment processes and biological treatment processes .This technique depend on electrochemical technology which being improved and developed to minimize the addition of chemicals. This study was aiming to investigate the efficiency of the electro-coagulation technique for removal of COD, BOD, Oil and Grease and TSS from Industrial Wastewater from Meat and Slaughterhouse industry in Tanta, Gharbeya, Egypt. Electro-coagulation is depend on passing of an electrical current (DC current) through a liquid, using an anode electrode and cathode electrode. In present study mixed electrodes of iron and aluminum are used and under the optimum condition of current density = 20 mA/cm2, distance between electrodes = 5 cm and retention time = 40 min. It maximum removals efficiency of COD, BOD, TSS, and oil & grease were 96.6%, 96%, 94.5%, 98.1% respectively.