A manually operated Jatropha fruit decorticator was designed, constructed and tested. The results of the study show that moisture content of the fruits and concave clearance between concave sieve and rotating blades, significantly affected the performance indicators. The decorticator works more efficiently as the moisture content of the fruit decreases with an optimum clearance between the concave and the blade. The decortications efficiency of the machine decreases with increase in fruit moisture content, while percentages of broken seed with dust decreased with increase in moisture content. It was found that the best set of conditions under which the decorticator can be operated is at fruit moisture content of 7.97% d.b. with concave clearance of 21 mm between the concave and the blade at which the maximum whole seeds of 67.94% can be achieved and machine efficiency of 90.96% can be obtained. The decorticator does not require electricity for its operation, hence, the problem of the frequent power outages that characterize in India has no effect on it. Also, because of its cheap cost to manufacture from locally-available materials, it is likely to satisfy a niche market in India and other developing country. Its use would help subsistence farmers to get onto the first rung of the wealth-creating ladder