The effect of smoking on the human body is multifactorial, due to chemical carcinogens, ionizing radiation, thermal, toxic, irritating and general resorption action. Thus, the question of studying the effect of smoking on the condition of periodontal tissues in teenagers and young adults is relevant. Purpose - to study the effect of harmful smoking habits on the condition of periodontal tissues in teenagers and young adults. Materials and methods. The dental status of 114 adolescents and young people (from 15 to 24 years old) was studied, which were divided into groups: group I involved 26 people who regularly smoke traditional cigarettes; to the second group - 22 people who regularly smoke electronic cigarettes (Vapi); to group III - 23 people who regularly smoke tobacco heaters (IQOS); to group IV - 43 people without a bad habit of smoking. The prevalence of periodontal diseases, OHI-S index, PMA index, PBI index was established. Results. It was found that the prevalence of periodontal disease averaged 72.36%. In the subjects of group I - the OHI-S index was equal to 1.77±0.02 points, in the subjects of group II - 1.53±0.01 points, in the subjects of group III - 1.46±0.02 points, in the subjects of group IV groups - 0.87±0.03 points. In persons of group I the value of the PMA index was 38.6±3.26%, in persons of group II - 33.7±2.52%, in persons of group III - 31.6±1.84%, in persons of group IV - 22.8±2.73%. The bleeding index of PBI in persons of group I was 1.18±0.02 points, in persons of group II - 1.43±0.03 points, in persons of group III - 1.39±0.02 points, in persons of group IV - 1.27±0.01 points. Conclusions. The study found a negative effect of bad smoking habits on the condition of periodontal tissues in teenagers and young adults. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local ethics committee of the participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the author. Key words: teenagers, young adults, prevalence of periodontal diseases, OHI-S hygiene index, PMA, PBI, smoking.