The design and fabrication of a power operated maize shelling machine was carried out in the engineering workshop of both Allamit Nigeria Limited, odo-ona, Ibadan and Federal College of Agriculture Moor Plantation, Ibadan, Oyo–State, Nigeria. The length, width and height of the machine are respectively 830mm, 605mm and 950mm. the machine can easily be carried with vehicle to a farm for operation. The performance evaluation was carried out using the NIS standard. This involved using three pulleys to vary the shaft shelling speed from 623rpm to 823rpm to 886rmp at moisture content of a maize cob viz: 13%, 15% and 17% respectively. Result showed that shelling efficiency, cleaning efficiency, grain recovery efficiency and output capacity were 87.08%, 95.89% and 623.99 kg/hr respectively which were at highest values at 13% moisture contents of maize and at 886rpm shelling speed. Thus, shelling of maize at 13% moisture content dry basis using 886rpm shelling speed resulted into the highest efficiencies and capacity of the machine when compared with other moisture contents and shelling speeds. Result showed that shelling efficiency, cleaning efficiency grain recovery efficiency and output capacity were 87.08%, 95.89%, 95.48% and 623.99 kg/hr respectively which were the highest values at 13% moisture contents of maize and at 886rpm shelling speed.