A ripple mill is an Australian invention and was first used to crack and grind grains and seeds such as peas, wheat, soya beans, etc. The mill was first applied to crack palm nuts (wet and dried) in a few mifis in Papua N’ew Guinea and Indonesia only in the last one to two years. Currently, Malaysian mifis are just beginning to evaluate its on-line performance. This paper describes the process performance of a ripple mifi in cracking wet nuts. The trial was conducted in a 20-tonne FFB/hr mill over 15 running days.