Effects of microwave and ultrasonication on chitin extraction time were investigated in this study. Chitin was extracted from ground crab shell by demineralization in 1.0 N HCl solution at 25$^{circ}C$ with or without ultrasonication and deproteinization in 1.0 NaOH solution at 100$^{circ}C$ without ultrasonication and at 70$^{circ}C$ with ultrasonication. Microwave treatment was also used for deproteinization with 5 min heating and 5 min standing without microwave. The changes in color difference, the contents of ash, calcium and nitrogen were measured during demineralization and deproteinization. Ultrasonication of 4 hr in 1.0 N HCl solution for removal of calcium and 1.5 hr of microwave heating in 1.0 N NaOH for deproteinization corresponded to 6 hr in 0.1 N HCl and 2 hr in 1.0 N NaOH of heating at 100$^{circ}C$ without those treatments, respectively. The data obtained showed that these treatments were effective reduction of chitin extraction time by 25${sim}$33% for chitin preparation. The chitin obtained from these ultrasonication and microwave treatments resulted 0.55% of ash, 0.25% of calcium, 2.47% of nitrogen and 20.64% of yield ratio. Those treatments selected were also reduced the darkness development time of the chitin solution during demineralization and deproteinization.