This study was conducted to determine the effects of electro disinfection against Escherichia coli and Coliform in water by using a platinum-platinum (pt / pt) electrode. Disinfection is a method to kill unwanted bacteria contained in the water, such as pathogenic bacteria as the cause of various diseases. Electro disinfection process is done by using a reactor and a pair of electrodes connected to the power supply (DC). The electrodes used are platinum (Pt) as the cathode and the anode. This study was conducted during the first hour. Research results from the analysis by the method of MPN (Most Probable Number) to determine the number of Coliform bacteria and Esterichia Coli dead, but it also tests the peroxide and the pH of the water after electrolyzed with a variety of voltages. The results showed that the optimum voltage to kill Coliform bacteria and Esterichia Coli found in voltage of 5 Volt and 10 Volt. From the test results peroxide is also known that the voltage is 5 Volt and 10 Volt has a greater concentration evident as 0,2565 mg/L and 8,504 mg/L , as well as the pH measurements after the electrolyzed water showed a pH range of between 7.66 to 8.21. 
Keywords: Electro Disinfection, Coliform, Eschericia Coli, MPN (Most Probable   Number), pH, Hidrogen Peroksida.