Most of Ethiopian farmers thresh and clean the grain by using traditional method but this method is very tiresome and time consuming. Therefore, this study focused on pedal powered grain threshing and cleaning machine in order to reduce and avoid those types of problems. It is a simple machine and operated by human with the help of pedal mechanism which reduces the total machine cost. The machine consists different components, such as gear, pedal, chain and belt, flywheel, fan, natural rubber and screening sieve. And in order to design and manufacture those components of the machine, different methodologies and material selections were used with CAD model of the machine. Using one power source to transmit power to different components by using chains and the grain is threshed with the help of threshing drum. After the grain is threshed, it will be screening by the principles of vibration. After screening process, the threshed grain goes to the rubbing section in order to clean the grain for further process. The rubbing section uses one rotating natural rubber and the other one is fixed to clean the grain. During rubbing process, there are some amount of scrap which is the unnecessary part of the grain and must be avoided by using fan system. The test is performed only on a single grain, which was wheat because of lack of grains for test. The design focuses basically on the four types of grains which are wheat, barley, rice and oat. The total efficiency of the threshing drum is 92.5% which is good and the only loss of the grain is 7.5%. The total cost of the machine is 12,663 birr. This machine has different advantages in terms of cost, improving time consuming, reducing labor force and reducing human power consumption