OBJECTIVES: To estimate the costs of once-daily fixed dose combination (FDC) abacavir/lamivudine (ABC/3TC) compared with twice-daily combination of its individual components (ABC+3TC) and twice-daily FDC zidovudine/lamivudine (ZDV/3TC) in efavirenz (EFV)-based regimens for treatment-naïve adults with HIV infection in Russia. METHODS: An Excel based model was developed to estimate the costs over 48- and 96-week time horizon for three compared regimens. Probabilities of switching to alternative and 2d line therapy due to low adherence and side effects were estimated for each regimen based on literature search. Costs of antiretroviral drugs in the 1st and 2d line of therapy and routine follow-up costs were calculated based on prices of state procurements in the framework of national project of HIV prevention and the tariffs of the Russian healthcare system in 2012. One-way sensitivity analysis was performed. RESULTS: ABC/3TC+EFV is not associated with more costs vs ABC + 3TC + EFV regimen  and even saves approximately 3390.60 rub (€80.30) per patient over 96 weeks of treatment. The sensitivity analysis showed that ABC/3TC FDC remains to be cost saving compared with ABC+3TC as long as the its package price is less than 6564.17 rub (€155.46) while keeping other model parameters unchanged. Still ABC/3TC+EFV is 28% more expensive than ZDV/3TC+EFV, though more effective and safe treatment option: the difference in costs vs ABC/3TC+EFV is 45267.05 rub. (€1,072.05) per patient over 96 weeks. CONCLUSIONS: FDC ABC/3TC may be considered as a more efficient and convenient treatment option than its monocomponents combination for first-line antiretroviral therapy of HIV patients in Russia. FDC ABC/3TC is more expensive vs ZDV/3TC, but the difference in costs seems appropriate for more safe and convenient alternative.