Objective: To evaluate the expression of extracellular matrix metalloproteinase inducer (EMMPRIN) in healthy and inflamed human gingiva. Method and Materials: Tissue samples from 9 healthy specimens and 21 specimens with chronic periodontitis were collected. The expression of EMMPRIN protein was detected with immunohistochemical staining and Western blot analysis. Results: EMMPRIN was mainly localized in keratinocytes of healthy human gingival tissues; in inflamed gingival tissues, EMMPRIN protein could be detected in keratinocytes, fibroblasts, and inflammatory cells. In addition, EMMPRIN expression level in the inflamed gingiva was increased dramatically compared to that in healthy tissue (P .05). Using Western blot analysis, EMMPRIN protein was also found to express in both healthy and inflamed gingiva, and the level of EMMPRIN in inflamed gingiva was significantly higher than that in healthy control subjects (P .05). Conclusion: EMMPRIN might be involved in the physiologic and pathologic states of periodontal tissues. Schlagwörter: extracellular matrix metalloproteinase inducer, gingiva, matrix metalloproteinase, periodontitis