Objectives : The aim of this research was to examine the most frequent pathological changes of the oral mucosa in children and adolescents in the oral medicine clinic of KBC Split between the opening of the clinic in September 2019 till March 2022. Materials and methods: 37 respondents took part in the research, for whom anamnestic data on gender, age, and any other diseases and medications taken by the respondents were retrospectively taken. Data were also taken from the records of the clinical examination, namely: type of lesion, nature of the lesion (acute/chronic/recurrent), localization of the lesion, subjective symptoms, need for therapy and type of therapy. Data were entered into spreadsheets and descriptive statistics were made. Results: In the oral medicine clinic of KBC Split, the majority of respondents are women (72.97 %). The most common change in the oral cavity is geographic tongue, which occurred in 32.43 % of respondents. The majority of respondents (74.28 %) had changes of a chronic nature, and the most common was mucosal exfoliation, in 35.14 % of cases. The most common localization of pathological changes was the tongue, in 35.14 % of respondents. Among the symptoms, the most common symptom was burning (24.32 %). Less than half of the respondents (45.95 %) needed treatment for changes in the oral mucosa, and for those who needed it, it was mostly local therapy (27,03 %). Conclusions: Based on the obtained results, we can conclude that the most frequent change in the oral mucosa in children and adolescents is geographic tongue, and accordingly, the most common lesion is exfoliation of the mucosa and the most common localization is the tongue. Most of the respondents had subjective symptoms in the oral cavity, and the most common was burning.