Summary Aims: The aims of this study was to examine the knowledge and attitudes of health care workers and non-health care workers about HIV / AIDS, to determine the difference in knowledge between these two groups of respondents, to determine the level of stigma and discrimination by respondents and to assess the need for staff education on HIV - AIDS infection. Methods: The survey method was used in the paper. Each respondent independently completed an anonymous questionnaire that included socio-demographic and knowledge-related questions about HIV / AIDS, as well as questions used to assess respondents attitudes toward people living with HIV / AIDS. Methods of descriptive statistics were used in the paper, namely arithmetic mean and standard deviation for normally distributed values, while for variables where the distribution deviated from normal, the median and interquartile range were used. The normality of the distribution was previously examined by the Kolmogorov-Smirnov test. The hypotheses were tested using the Mann-Whitney U test, and the T-test. The analysis was performed in the statistical software SPSS 25. Results: A statistically significantly higher level of knowledge was found in health care workers compared to non-health care workers (Z = 6.54; p <0.001). After testing the attitudes and levels of stigma of the respondents, it was also found that the value was statistically significantly lower than the cut off value (t = 8.27; p <0.001), ie there is a low level of stigma and discrimination against HIV / AIDS patients, which is the opposite of expected. Conclusions: With knowledge we can fight stigma and discrimination. Education of all employees in the health system, as well as health education of the population is an important factor in combating stigma and discrimination, and by educating the population and patients we can prevent the spread and transmission of HIV infection in the future. Key words: HIV / AIDS, knowledge, attitudes, health and non-health workers, stigma, discrimination Thesis contains : pages, figures, tables, supplements, references Original in: Croatian