Ndukwu M.C., Asoegwu S.N, 2010. Functional performance of a vertical-shaft centrifugal palm nut cracker. Res. Agr. Eng., 56: 77-83.A vertical-shaft centrifugal palm nut cracker was presented and evaluated. The cracker efficiency and kernel breakage ratio are some of the most important parameters for evaluating the cracker performance. From the result of this work, the two parameters are function of cracking speed, moisture content and feed rate. The result showed that for the lowest speed of 1,650 r/min, and the highest feed rate of 880 kg/h and for all moisture contents, the cracking efficiency was not up to 65%, therefore the efficiency increases with an increase in machine speed and a decrease in feed rate. The kernel breakage ratio ranged from 0-0.18 (0-18%) for all feed rates and moisture contents. It increased with moisture content and cracking speed, but decreased with feed rate. All the parameters determined have a linear relationship with moisture content.