Objective: The aim of this study is to assay the pathogen inactivation process with amotosalen on the quality of platelet concentrates obtained by apheresis and compare quality control results before and after the inactivation process. Materials and methods: The study includes laboratory quality control results of non-inactivated and inactivated platelet concentrates throughout the year 2021. obtained at KBC Osijek. The results were statistically compared before and after the inactivation method. Hematological quality control values were determined on a Mindray BC-3600 automatic analyzer, and the number of remaining leukocytes was determined on the Adam rWBC automatic device. Pathogen inactivation method was performed on the Intercept, Cerus device using the photoactivation method with amotosalen. The results of the analysis are shown graphically and table-like, showing the mean values for each quality control parameter. To compare numarical data, t-test for repeated measures and Wilcoxon's test were used. The level of statistical significance was set at α= 0.05, and the analysis was performed in the statistical tool RStudio (Inca 4.2.1. RStudio). Results: From the obtained results, a statistically significant difference was found for weight and volume of the concentrates, number of platelets, number of equivalent doses and number of remaining leukocytes per dose. Due to the inactivation process, there was a decrease in the volume of the concentrates and consequently a decrease in the number of platelets, which was the most important quality control parameter for this study. Conclusion: The study concluded that the process of pathogen inactivation on the Intercept device leads to a reduction in the number of platelets, the weight and volume of concentrates, the number of equivalent doses and the number of remaining leukocytes due to the inactivation process, but platelet concentrates that are subjected to inactivation process still meet the prescribed quality control criteria and are safe for use in transfusion treatment.