OBJECTIVES: The aim was to assess direct medical costs of HIV patients, based on CD4+ lymphocyte count and duration since diagnosis in the Czech setting. METHODS: We analyzed retrospectively costs of HIV patients in a single center. The analyzed sample included patients with a disease history of 12 month and longer, who regularly visited the center. Resource use, derived from the hospital information system, included services delivered at the HIV center and other hospital wards. The retrospective period covered up to 36 months; average annual costs were calculated. Resource use was analyzed separately for (a) groups of CD4+ count (˂200; 200-499; ≥500); (b) time since diagnosis (˂5 years; 5-10 years; ˃10 years). For comparison, two-sided Student’s t-test was used; to achieve normal distribution, values were transformed to common logarithms. Costs are stated in € (1€=25.5CZK). RESULTS: A total 100 patients (about 10-15% of all HIV treated in the Czech Republic) were included. The mean age was 41.9 years (range 23-71), time since diagnosis 5.8 years (range 1-26), and period of assessment 30.5 months. Average total annual costs were highest for CD4+ ˂200 (22,905€; p˂0.05) vs. CD4+ 200-499 (17,801€) and CD4+ ˃500 (17,043€). HIV medication accounted for the majority of costs in all three subgroups (range 62% in CD4+ ˂200 to 88% in CD4+ ˃500). Patients with a disease duration of ˃10 years had highest annual costs of 22,841€ (p˂0.05) compared to 15,783€ (duration 5-10 years) and 16,777€ (˂5 years). HIV-medication accounted for the majority of costs here as well (from 70% to 88%; NS). In this analysis 17 % of costs in patients with disease duration of ˃10 years were due to hospitalization vs. 5 % in both other groups (NS). CONCLUSIONS: Similarly to published literature, we found highest costs in patients with low CD4+ lymphocytes and longer disease duration.