Introduction: Adolescent mental health, particularly among medical school students, is critical to their academic success and overall well-being. Objective: To examine the frequency of depression, anxiety and stress among students of medical schools in Zadar and Rijeka. To compare the frequency of depression, anxiety and stress among medical school students based on their place of residence. To examine whether there are gender differences in relation to the occurrence of depression, anxiety and stress. To examine whether there is a connection between the occurrence of depression, anxiety and stress related to satisfaction with school performance. Subjects and methods: 120 students from medical schools in Zadar and Rijeka participated in the research, 60 students from each school. 3rd, 4th, and 5th grade high school students participated in the research. The DASS-21 scale was used to assess depression, anxiety and stress. Additionally, sociodemographic data and five related to student satisfaction with school success were collected. Results: The research did not confirm the hypothesis that female students of medical schools in Rijeka have a higher level of depression, anxiety and stress compared to female students from Zadar. The hypothesis that there are significant differences in the levels of depression, anxiety and stress between male and female medical school students was not confirmed, since the results did not show a statistically significant difference in the overall scores on the DASS-21 scale between the sexes. The hypothesis that female students with higher levels of depression, anxiety and stress have lower satisfaction with school performance was confirmed, as a negative correlation was observed between results on the DASS-21 scale and satisfaction with school performance. Conclusion: Depression, anxiety and stress represent significant challenges for medical school students, affecting their satisfaction with school performance and overall well-being. In order to improve the mental health of students, schools should take concrete measures that include the introduction of prevention and intervention programs aimed at reducing depression, anxiety and stress.