This study was undertaken to examine the levels of insoluble immune complexes in healthy and inflamed gingiva by measuring citrate buffer-elutable IgG. After establishment a clinically healthy gingiva by continuous toothbrushing for 6 weeks, the experimental gingivitis was induced by placement of silk floss ligature to accelerate plaque formation for 1 week, 1 and 3 months. The excised gingiva was prepared by the elution procedure with PBS and citrate buffer. The concentration of PBS-elutable IgG in gingiva was measured by SRID, besides the citrate bufferelutable IgG was determined by ELISA and RIA. As a results ; 1) The amount of PBS-elutable IgG had a tendenvy to increase in inflamed gingiva at each experimental period and the IgG level was significantly higher at 3 months experimental period than the healthy. 2) The citrate buffer-elutable IgG significantly increased in inflamed gingiva at each experimental period and the rate of increase was more prominent with advancing gingivitis. 3) There was an increase in ratio of citrate bufferto PBS-elutable IgG at each experimental period as compared with at the healthy. 4) As shown r=0. 945 in a coefficient of correlation, a close correlation between ELISA and RIA was found.