This study investigated the degradation patterns of chitin oligomers for Bacillus thuringiensis chitinase (Btchitinase) and recombinant Btchitinase (rBtchitinase) produced by Escherichia coli expression system. N-acetyl chito hexamer and three colloidal chitins - crab shell (CC), squid pen (SC), and mealworm (MC) - were used as substrates. Btchitinase and rBtchitinase showed the strongest activity at 60oC (29.4 and 40.5 units/mg protein, respectively). Btchitinase and rBtchitinase displayed the strongest activity at pH 5 (21.6 and 27.8 units/mg protein, respectively). Btchitinase mainly produced N-acetyl-chito dimer[(GlcNAc)2] from (GlcNAc)6, whereas rBtchitinase mainly produced (GlcNAc)2 and (GlcNAc)3 from (GlcNAc)6. Degradation of (GlcNAc)6 catalyzed by rBtchitinase yielded by 714.9 ppm the greatest amount of (GlcNAc)2. The amounts of (GlcNAc)2produced by Btchitinase and rBtchitinase were highest in MC, followed by CC and SC. (GlcNAc)2 was produced in the greatest quantity from the MC substrate after 3 days of incubation by Btchitinase and rBtchitinase (112.2 and 104.7 ppm, respectively).