Research aim: The aim of this research was to find out what the opinions of fourth and fifth grade students of medical school (nurses) on people with mental illnesses are and see how they differ with regard to gender, class, place of residence, school and final grade of the class they had previously finished. Participants and methods: A cross-sectional study has been conducted on 101 participants. The participants were fourth and fifth-grade medical school students from Čakovec High School (Srednja škola Čakovec) and Varaždin Medical School (Medicinska škola Varaždin). The instrument used was a questionnaire that consisted of demographic questions and OMS-HC scale for collecting data about opinions on people with mental illnesses. Categorical data have been represented by absolute and relative frequencies. Numerical data have been described using the arithmetic mean and standard deviation or median and interquartile range, depending on the distribution normality. The normality of the distribution of numeric variables has been tested using Shapiro–Wilk test. The differences in numerical variables between two independent groups have been tested using Student’s t-test and Mann–Whitney U test, whereas differences between three independent groups have been tested using the analysis of variance. All P values were two-tailed. The significance level was Alpha = 0,05. The statistical analysis has been made using statistical programme called MedCalc Statistical Software version 14.12.0 0 (MedCalc Software bvba, Ostend, Belgium; http://www.medcalc.org; 2014). Results: There is no difference in students’ opinion with regard to their gender, class, place of residence, school and previous final grade. According to the OMS HC scale, fifth-grade students have a more positive view of people with mental illnesses. Conclusion: Given results show that fifth-grade students have a more positive opinion about people with mental illnesses. Gender, class, place of residence, school and previous final grade are not determinants of change in opinion about people with mental illnesses.