Objective: To compare the levels of matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in patients with gingivitis and periodontitis and in healthy controls. Methods: Levels of MMP-2, MMP-9, and TIMP-1 were determined by ELISA in patients with healthy gingiva (n = 16), gingivitis (n = 18), and periodontitis (n = 25). The subjects with periodontitis were examined before and 1 month after basic periodontal therapy. Results: Slightly higher concentrations of MMP-9 were observed in patients with periodontitis but without statistical significance. MMP-2 was found to be slightly diminished in these patients. The lowest concentrations of MMP inhibitor (TIMP-1) were observed in patients with periodontitis, in whom the concentrations increased after periodontal treatment. Conclusion: The reduction in TIMP-1 concentrations in disease situations suggests a breakdown of the balance between the amount of MMPs and their inhibitor. Keywords: gingivitis, metalloproteinase, periodontitis, tissue inhibitor of matrix metalloproteinase-1