A cowpea threshing machine was designed, fabricated and evaluated in the Department of Agricultural and Bio-Environmental Engineering Technology, Rufus Giwa Polytechnic, Owo, Ondo State, Nigeria. The machine was fabricated using locally available materials with the primary aim of reducing drudgery attached to the traditional method of threshing cowpea. The machine consists of the hopper, the threshing unit, the cleaning unit and the outlet. A 3-horsepower single phase electric motor served as the prime mover for the thresher. The machine was evaluated based on the varying operating speeds of 450 rpm, 550 rpm and 650 rpm and moisture contents of 13.5%, 14.5% and 15.5% respectively. The results showed that the machine efficiency increased with an increase in feed rate and a decrease in moisture content. An optimum level of 94.4% efficiency was observed at the speed of 650 rpm and moisture content of 13.5%.