Abstract Smokers have a risk of developing periodontal disease. Matrix metalloproteinases (MMP) play a significant role in periodontal tissue destruction. In this study possible relationship between smoking and gingival tissue expression of gelatinases in chronic periodontitis patients relative to periodontally healthy subjects was investigated. Forty chronic periodontitis patients (20 smokers and 20 non-smokers) and forty periodontally healthy subjects (20 smokers and 20 non-smokers) were enrolled. The clinical periodontal measurements recorded, and gingival tissues harvested after that. After histologic evaluation, matrix metalloproteinases -2 and -9 expressions were analyzed immunohistochemically. In nonsmokers, higher expression of metalloproteinases -2 and -9 detected in chronic periodontitis group compared to the periodontally healthy group. In the smoker chronic periodontitis group, the expression of metalloproteinases-2 was lower than nonsmoker chronic periodontitis group. Statistically significant differences detected between smoker and nonsmoker periodontally healthy groups in metalloproteinases-2 expression. For metalloproteinases-9 expression, smoker chronic periodontitis group has lower values than nonsmoker chronic periodontitis group. In periodontally healthy group smokers showed higher metalloproteinases -9 expressions than non- smokers. Present findings support the role of gelatinases in chronic periodontitis pathogenesis. Based on the current results we conclude that smoking alters the expression of gelatinases in gingival tissues.