Bacillus thuringiensis GS-2 was incubated on various culture media to investigate the concurrent expression patterns of chitinase and chitosanase isozymes by SDS-PAGE. Chitinase activity increased rapidly with a maximum level (11 units/mL) after 5 days of incubation in colloidal chitin medium. B. thuringiensis GS-2 had strong antifungal activity on PDA medium for Rhizoctonia solani and Fusarium oxysporum. Four chitinase isozymes were expressed on the SDS-PAGE gel as active bands (about 70, 65, 37, and 35 kDa) on LB medium after incubation. The chitosanase isozyme of 39 kDa was expressed strongly on the SDSPAGE gel in LB medium and was expressed lightly on the SDS-PAGE gel after incubation in 0.5% chitosan powder and 0.5% chitosan beads medium. Four chitinase isozymes (C1, C2, C3, and C4) were expressed on 2-D gel at 5 h and 12 h after incubation. Three chitinase isozymes (C1, C3, and C4) were expressed on 2-D gel at 1 h and 2 h after incubation. Isoelectric point (pI) of chitinase isozymes was range from 3.5 to 9.