Abstract： Objective To compare the different apoptosis in gingival epithelium between smokers and non-smokers. Methods 21 healthy male patients of crown lengthening surgery without systemic or distinct gingival diseases, the age ranged from 30 to 45years old. Ten normal gingival epithelium were chosen as control.Apoptosis was identified by the terminal deoxy-transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) method. Differences among the three groups were analyzed using Student-Newman-Keuls (SNK).The criteria for statistical significance were accepted at the probability level P ＜ 0. 05. SP immunohistochemicalmethod was used to detect the expression of Bcl-2 protein. Results Apoptosis in human gingival epithelium were significant difference between smokers and non-smokers ( P ＜ 0. 01 ). The expression of Bcl-2 was weaker in gingival epithelium of smokers. Conclusion We conclude that exposure to cigarette smoke can increase apoptosis in gingival epithelium and interfere with normal metabolism.