Periodontal disease is a chronic multi-factorial disease. Many studies evident that tobacco smoking is one of the most significant risk factors associated with the development and progression of such disease. The effect of tobacco smoking on periodontal tissues is cumulative, meaning that it depends on the number of cigarettes smoked daily and the duration of the habit. In the course of many research studies, the results also show that smokers have more sites with deep periodontal pockets, they more often suffer from loss of alveolar bone high and loss of clinical attachment, as well as loss of teeth in general. Beside that, smokers have larger amount off accumulated dental tartar. Since tartar is one of the major reasons for development of periodontal disease, the probability of having advanced periodontal disease is a greater. In addition, researches point out that cigarette smokers comparing to non-smokers harbor larger amount of virulent bacteria types causing periodontitis. The level of plaque in smokers is equal as non-smokers, but smokers show less gingival inflamatory change and bleeding on probing was less evident. The major clinical implication of these findings is that the masking of gingival bleeding in smokers may lead to a failure to recognize the presence of periodontal disease. Due to negative influence of nicotine on the treatment mecanisms, smokers have slower response and less effect on periodontal tissue therapy. Smoking cessation, beside that favorably influence overall human health, drastically mitigates, effects on periodontal structures, positively affects the process and the end result of periodontal therapy, as well as diagnosis itself. With respect to their periodontal status, former smokers response to a therapy is alike response of never-smokers regardless duration of the habit.