Melon seed has been described as very important oilseed crop that serves numerous food purposes across Nigeria. Since melon seed is within a shell, dehusking or decorticating or dehulling or shelling, it is expedient so as to use it for food. To carry out the process of removal of the shell, a melon decorticating machine was designed and developed. The machine was designed based on standard engineering design procedures. A CAD drawing was used to develop the machine and a detailed design of the machine was implemented. The CAD drawing was fabricated. The machine was built using materials available locally and it consists of the following components the melon shelling machine were the hopper, the shelling chamber, the base, the blower unit, the body frame, the blade, switch, fan regulator, feed controller, blade housing, electric motor, motor holder, bolt and nut. Two different performance evaluation were carried out: one, a comparison based on time of shelling using both the designed machine and the manual shelling method and two, the performance evaluation was carried out for different Melon seeds of three (3) varying moisture contents. The parameters evaluated include decorticating efficiency, percentage of decorticated seed and damaged, machine performance and capacity. Results from the developed machine shows a shelling efficiency of 73.1% with seed damage percent of 14.3% when using moisture content of 30%d.b. while, for the manual shelling was reported to be of a shelling efficiency of 10%, 15.7% and 20.2% with 20.2% being its highest efficiency which is seen to be very small compared to that of the machine. Shelling speed of the machine and moisture content of the seed Melon affects the rate, efficiency and percentage of damage to the seeds. This design and the set of conditions selected were the most preferred due to their speed operation, less damage to the seeds and minimal expenditure of human energy. The developed machine does not require skilled labor, and this melon sheller can effectively address the challenges of the traditional method of decorticating melon.