In this study, chemical oxygen demand (COD) removal from medical waste sterilization plant wastewater by electrocoagulation is investigated. Biological and chemical methods are not sufficient for the desired removal efficiencies therefore EC is applied to medical waste sterilization plant (MWSP) wastewater. The process is tested using iron and aluminum electrodes, parallel and serial connections, and different initial pH (4, 5, 7, 8) and current density (1, 0.75, 0.5 A/m(2)) values. COD removal efficiency of the process is analyzed as a function of operating time, electrode material, initial pH, current density and electrode connection type at room temperature. The initial pH value is found to have the largest effect on removal efficiencies, at different connection types and current densities. Approximate removal efficiencies are 51%, 63%, 89% and 62% for pH 4, 5, 7 and 8, respectively. The electrode connection type also affects the removal efficiency. Maximum COD removal efficiency (98%) is obtained using a 1 A/m(2) current density, a 30-min operating time, an initial pH of 7, and Fe-serial connections.