The aim of the study was to determine whether non-surgical treatment of periodontal disease affects changes in neopterin levels in the saliva of smokers and non-smokers. The study was conducted among patients of the Periodontal Diseases Clinic of the University Dental Clinic in Krakow in 2015-2017. The study covered two groups of patients (smokers and non-smokers) with periodontal disease. During the study some periodontal indicators were assessed: PUW, API, mSBI, PPD, GI, CAL, a mobilty of tooth, a furcation defect. Level of neopterin was determined in the salivary sample taken using the Human Neopterin ELISA Kit.The study showed:1. No effect of non-surgical treatment of periodontitis on neopterin level in the saliva of smokers and non-smokers2. Lower values of mSBI and GI indices in smokers.3. Differences in the effectiveness of the non-surgical treatment of periodontitis in the studied groups4. No effect of smoking habit on the level of neopterin in saliva5. Positive correlation between the API, mSBI, GI and PPD indicators and the level of neopterin in saliva.