Background: In 2020, Polish experts recommended the use of the guidelines of the American Association of Clini cal Endocrinologist and the American College of Endocrinology (AACE/ACE) in the diagnosis of obesity instead of the 1998 WHO criteria. Thus, obesity can be also diagnosed in patients with BMI 25.0-29.9 if there are complicaitons related to the excess body weight including infertility and hypogonadism, asthma, sleep apnea, gastroesophageal reflux disease, stress urinary incontinence, osteoarthritis and depression. Material and methods: The aim of the study was to assess the prevalence of obesity diagnosed according to the new criteria in the group of Polish social media users. Results: Among the respondents, 9.7% had a BMI below 18.5 kg/m2, 63.9% declared normal BMI, and 18.8% had BMI 25.0-29.9 kg/m2. The value of BMI ≥ 30 kg/m2, equivalent to the diagnosis of obesity according to WHO, was found in 7.6% of the respondents. For comparison, the prevalence of obesity according to the AACE/ACE criteria was more than twice as high (17.2%, p < 0.05). Conclusions: Concluding, according to the new criteria, more respondents were diagnosed with obesity compared to WHO criteria. The results of the study indicate that the application of the new diagnostic criteria may enable earlier diagnosis and thus earlier treatment of obesity. Samek G, Szulc A, Dardzińska JA. The prevalence of obesity diagnosed by diefrent diagnostic criteria in Polish social-media users. Eur J Transl Clin Med. 2023;6(1):25-30.