De-husking of sunflower seed is an important process prior to its oil extraction. Manual de-husking of sunflower seeds is a time consuming and tedious operation. Therefore, the effectiveness of a shear and impaction type decorticator for sunflower seeds was studied and evaluated for performance parameters. The performance test for maximum seed yield was evaluated on the basis of various performance indicators, which includes percentage of whole seed, broken seed, un-husked seeds, machine capacity and decortication efficiency. These performance indicators of the decorticator were evaluated at three different seed moisture contents (9%, 12% and 14% d.b.) and at constant cylinder speed (56 rpm). The clearance between rotating cylinder and concave was fixed at 5 mm for optimum force. The best results of 52.73% recovery of whole seeds and machine capacity of 6.08 kg/h were recorded at seed moisture content of 9% (d.b.) and broken percentage was less 0.76% under the seeds used at 14% moisture content and the highest dehusking efficiency of 98.43% was observed with the decortication of 12% moisture content sunflower seeds.