OBJECTIVES: to compare treatment costs for the fixed dose combination (FDC) tenofovir and emtricitabine (TDF/FTC) versus FDC abacavir and lamivudine (АВС/3TC) each in combination with efavirenz (EFV) in treatment-naïve adults with HIV-1 infection in Russia. METHODS: A mathematical model was developed in Microsoft Excel to evaluate costs of treatment, including drug (1st and 2nd lines of therapy) and patient management costs. In the model individuals remained on their current regimen or moved to the 2nd line of therapy after the first 48 weeks on therapy. Transition probabilities were based on the proportion of patients with viral response measured as HIV-1 RNA < 50 copies per milliliter from the clinical trial with TDF/FTC + EFV vs АВС/3TC + EFV head-to-head comparison. Cost calculations were based on registered drug prices, reimbursement rates in public medical insurance and data on government procurement in Russia in 2014. RESULTS: It was expected that after the 48 weeks of treatment 71.0% of patients in TDF/FTC + EFV group and 59.4% of ABC/3TC +EFV remain on the initial regimen. The total average costs per patient for 96 weeks of therapy, including drug (1st and 2nd lines of therapy) and patient management costs, were lower for TDF/FTC + EFV (€6,528) than for ABC/3TC + EFV group (€7,123).  CONCLUSIONS: FDC TDF/FTC in 1st line therapy in treatment-naïve adults with HIV-1 infection in combination with EFV was predicted to be cost-saving compared with FDC ABC/3TC+EFV for 96 weeks of treatment in Russian Federation.