This present study investigates Ni and Mg removal from electroplating wash-water employing electrocoagulation with aluminum electrodes. The simultaneous effects of various operating parameters were evaluated and optimized using a central composite design in terms of Ni, Mg removal, COD removal, energy consumption, and operating cost. At these optimum conditions (current density = 86.23 A/m(2), pH = 7.5, operating time = 60 min, and NaCl dose = 0.5 g/l), 97% Ni removal and 90% Mg removal was achieved with energy consumption of 22.45 kWh per kg Ni removed and operating cost being 4 $ per kg Ni removed. X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis were on the residue obtained.