Aims of this study were to analyze the immune status and kinetics of viral replication in individuals diagnosed with human immunodeficiency virus (HIV) in Croatia in the period from 2014 to 2017 and to compare the results with data from 2020. Potential differences in the number of cases of late presentation to HIV care and cases of advanced HIV infection in the observed time intervals were also investigated and additional parameters of cellular immunity and their possible connection with the kinetics of viral replication were analyzed. One-way analysis of variance and Bonferroni post-hoc test showed statistically significantly higher mean values of absolute number and percentage of CD4 + T-lymphocytes in individuals diagnosed with HIV in 2020 compared to people diagnosed with infection in 2016 and 2017. The Chi square test showed a statistically significant difference in the number of cases with advanced HIV disease at the time of diagnosis during the observed time period and patients diagnosed with the HIV infection in 2015 and 2020 showed the lowest percentages with late and very late presentation to care. The analysis of additional immunological parameters in relation to the reference values revealed elevated mean values of the percentage of CD8 + T-lymphocytes, CD8+/CD38+ T-lymphocytes and the percentage of activated T-lymphocytes as well as the ratio of CD8+ and CD4+ T-lymphocytes. The results of this research show that the most cases of HIV infection diagnosed in 2020. were detected before the onset of significant cellular immunity deficiency. Additional analyzes of immune status showed significant activation of cellular immunity in HIV-infected individuals.