Discovery, understanding, monitoring and prevention of drug side effects are relevant topics in the field of biology due to their great contribution to the protection of patient health. Health professionals, especially doctors and pharmacists, most often have the opportunity to notice and then report a side effect. Any reporting of side effects is important and can contribute to the safer use of medicines. The aim of this research was to examine the attitudes, knowledge and practice of pharmacists regarding the reporting of adverse drug reactions and to determine whether there are differences in the knowledge, practice and attitudes of pharmacists regarding pharmacovigilance and the reporting of adverse reactions in the Zagreb and Osijek-Baranja County. The research was conducted on a sample of 200 pharmacists in the Zagreb and Osijek area in the period from January to May 2023. The chi-square test and descriptive statistics are used in the analysis of obtained data. No statistically significant difference was found in the attitudes and knowledge of pharmacists about pharmacovigilance between pharmacists in the Zagreb and Osijek areas. There was a statistically significant difference in the frequency of reporting side effects for respiratory agents and thyroid medications among pharmacists in the two areas. The vast majority of participants have good knowledge and positive attitudes toward pharmacovigilance, but the practice of reporting suspected drug side effects among pharmacists is not satisfactory. This work points to the need to encourage pharmacists to report suspected side effects of drugs