Matrix metalloproteinases (MMPs), the key enzymes responsible for matrix degradation, are derived from polymorphonuclear leukocytes during the early stages of periodontitis. The present study determined the levels of GCF matrix metalloproteinase-2 (MMP-2) and metalloproteinase-9 (MMP-9) and salivary MMP-8 in patients with gingivitis and periodontitis and in healthy controls. Levels of crevicular MMP-2, MMP-9 and salivary MMP-8 were determined by ELISA in subjects with healthy gingiva (n = 15), gingivitis (n = 18) and periodontitis (n = 20). Significantly higher salivary MMP-8 and crevicular MMP-9 were observed in cases of periodontitis compared to gingivitis and healthy adults. On the other hand, crevicular MMP-2 levels in periodontitis subjects were lower than those in gingivitis and healthy subjects. The three MMP levels were highly correlated to probing depth, and bleeding on probing. Salivary MMP-8, crevicular MMP-2 and 9 may serve as biomarkers of periodontal disease and aid in early detection of periodontitis or gingivitis. (J. Oral Sci. 50, [53][54][55][56] 2008)