Smoking is implicated as one of the most significant risk factors for periodontal disease. The objective of this study was to examine the effect of cigarette smoke extract (CSE), on cultivation of and protein production by Porphyromonas gingivalis , a major periodontal pathogen. P. gingivalis were cultivated in the presence of CSE (0%, 2.5%, 5%, and 10%) solution, and their growth was measured by optical density. In addition, expression pattern of proteins produced by P. gingivalis under CSE influence, was examined by sodiumdodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). According to the results, the growth of P. gingivalis was inhibited by CSE in dose-dependent mode. SDS-PAGE analyses revealed minor difference in expression pattern of proteins. Results of this study suggest that CSE imposes an inhibitory influence on growth of P. gingivalis , and is capable of modulating protein expression in P. gingivalis.