This study was designed to compare the effects of treatment using chitosan membrane $(Nanogide-C^{(R)})$ resorbable barrier with control treated by polylactic acid/polylacticglycolic acid membrane(PLA/PLGA membrane, $Biomesh^{(R)}$). 44 furcation defecs from 44 patients with class 2 furcation degree were used for this study, 22 sites of them were treated by chitosan membrane as experimental group and 22 site were treated by PLA/PLGA membrane as control group. Clinical parameters including probing depth, gingival recession, attachment level and radiographic examination were evlauated at base line, 1 month, 2 month and 3 month. after surgery. Statistical test used to analyze these data included paired t-test, one way ANOVA. The results are as follows : 1. Probing depth was significanlly decreased in the two group and there were significant differences between groups(p<0.05). 2. Gingival recession was not significanlly increased in the two group and there were no significant differences between groups(p<0.05). 3. Loss of attachment was statistically decreased in the two group and there were no significant differences between groups(p<0.05). 4. Horizontal bone level was significanlly increased in the two group and there were significant differences between groups(p<0.05). On the basis of these results, chitoans resorbable membrane has similar potential to PLA/PLGA membrane in GTR for furcation defect.