In order to study the effects of cigarette smoking on periodontal tissue, gingival fibroblast from the smoking and nonsmoking groups were cultured and each group were treated with nicotine(50ng/ml,100ng/ml) and NNK(50ng/ml, 100ng/ml) to test their attachment ability at time intervals of 30minutes, 60minutes, 90minutes, 120minutes, and 240minutes. Using the same method, the growth each group treated with nicotine and NNK in order to compare their attachment ability and growth rate was done. The Results are as follows. 1. In comparing the attachment ability and growth rate between the smoking and non-smoking group were significantly higher in all time intervals. 2. When the attachment ability was com-pared among these two groups after treatment with nicotine and NNK, the non-smoking group showed decrease in attachment ability while the smoking group was not affected. 3. The growth rate of these two groups were compared after treating with nicotine and NNK. The growth rate of fibroblast from the non-smoking group decreased while fibroblast from the smoking group was not affected. These results suggest that fibroblast from the non-smoking group showed higher attachment ability, growth rate, and sensitivity to nicotine and NNK. This implies that fibroblast from the non-smoking group is a more reliable source in testing the cytotoxicity of nicotine and NNK. Also it could be reasonable to think that nicotine and NNK is a probable cause for problems in attachment and repair mechanism.