Abstract: Grinding characteristics of raw and parboiled soybean were evaluated in various wet grinding systems, namely, stone grinder, shearing grinder and colloid mill.The duration of grinding had inverse effect on the particle size and direct impact energy consumption in batch grinders.Stone grinder was the least energy efficient and special energy consumption for grinding raw soybean was 1.83 times as that of shearing grinder.Parboiled soybean required longer duration of grinding compared to raw soybean, consequently energy consumption was higher.All the three classical laws of grinding (Kick's, Rittinger's, and Bond's) seemed to be applicable while Rittinger's law show better suitability than the other two followed by Bond's law.Parboiled soybean slurry exhibited much greater viscosity than raw soybean but both displayed non-Newtonian pseudoplastic behavior.