Two experiments were conducted at Khon Kaen University, Nong Khai campus, Thailand during May to December 2015 to justify effects of chitosan of Experiment 1 on growth performance of rice-field crabs. The Experiment 1 had five chitosan treatments, i.e. 0, 1, 2, 3 and 4% (on dry matter basis). Experiment 2 had two treatments, i.e. the best treatment of Experiment 1 (T3) was chosen in comparison with flesh fish meat treatment. A Completely Randomized Design (CRD) with four replications was used for Experiments 1 and 2. The results of the Experiment 1 showed that a chitosan level of 2% of T3 gave significantly (p < 0.05) better growth performance on final weight gained, weight gained, average daily growth rate, specific growth rate and survival rate (%) of the rice-field crabs than the rest, except that of the feed conversion ratio where T1 (control) was the highest. Thus a chitosan level of 2% (T3) in the feed diet is recommended for rice-field crab culture. With the Experiment 2, the feed diet of T3 of Experiment 1, i.e. with 2% chitosan gave significantly (p < 0.05) higher survival rate (%) of rice-field crabs than the flesh fish meat of T1.