Electrorheological suspensions are suspensions of solid particles whose rheological behavior can be strongly modified by the application of an electric field. In this article, the electrorheological properties of suspensions containing chitin particles (and its derivative-carboxylmethyl chitosan particles) in silicone oil are reported for a range of suspension weight concentrations, applied field strengths, shear rates, etc. In these suspensions, glycerin was used as an activator. The adsorbed amount of glycerin, one of the electrorheological parameters, was also studied experimentally. The ER effect of the chitin suspension reaches the maximum at about 11% of weight concentration. The dependence of the experimentally determined dynamic yield stress on particle concentration and field strength is found to be similar to that reported for other systems. The dynamic yield stress is found to increase with the particle concentration and the applied electric field strength.