Fish products represent an extremely important segment in the human diet, which is reflected in the development of the fish industry. Therefore providing consumers with a wide range of fish products. Over the last few decades, this food industry has flourished primarily in terms of technology, which is evident through various new fish processing technologies. Freezing is a complex process that, if not done properly, contributes to the rapid deterioration of food. Proper process helps with preservation of the quality of fish and its nutritional values. The quality of the fish also depends on the treatment before the freezing procedure itself, as well as the method of storage. In this paper, a comparison of qualitative changes was made for fresh sardine stored at a temperature of 0 to 3°C and sardine frozen with IQF technology. The change in qualitative parameters was based on a change in chemical parameters such as a change in fats, proteins and water. The second part of the paper was based on microbiology, where the number of colonies of sulfite-reducing clostridia, Enterobacteriaceae and aerobic mesophilic bacteria was analyzed. Furthermore, in order to determine the correctness of the food itself, the degree of lipid oxidation was determined using the thiobarbiturate test and the peroxide number. A test was also made to determine the amount of histamine that is potentially dangerous to human health. Statistical analysis of chemical and microbiological parameters did not show significant changes between the fresh sample and the frozen sample of sardine. In addition, the analysis of the thiobarbiturate test for fresh sardines proved a significant difference in the number of malondialdehyde over time, which implies a certain degree of lipid oxidation. However, the thiobarbiturate test for frozen sardine did not reveal a significant change in the number of malondialdehyde, which indicates that there is no lipid oxidation in the sample of sardine frozen by IQF technology. Peroxide number in fresh and frozen fish samples showed no significant difference. Also, the amount of histamine in fresh and frozen sardines did not show a significant change.