A randomized multicenter 96-week study of an elsulfavirine (ESV), non-nucleoside reverse transcriptase inhibitor (NNRTI) of novel generation, in combination with 2 nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) was conducted in naive HIV adult patients, divided by 2 parts: 1) partially blind comparative to efavirenz (EFV) 48-week study, 2) open-label observational study during additional 48 weeks. High virological and immunological effectiveness maintained during the study: proportion of patients with HIV RNA <50 copies/ml in 48 weeks achieved 81,6%, in 96 weeks - 83,9% (MITT-analysis) and 91% (if patients withdrawn from the study due to other reasons not related to treatment were excluded). No resistance mutations were found in patients with viral replication blips (HIV RNA 50-1300 copies/ml). CD4+-lymphocytes count was increased by 187,5 at week 48 and 251,0 cells/mcl at week 96. Good tolerability and safety were confirmed during second year of treatment: no additional safety data which could influence benefit/risk ratio were recorded as well as withdrawal from the treatment due to adverse events. Serious adverse events, connected with treatment, allergic reactions were not registered during the whole 96-week study. Conclusion. Results of the 96-week study confirm earlier data from 48-week study on high efficacy and safety of ESV. Based on these data ESV was included into "National recommendations on dispensary follow-up and treatment of patients with HIV-infection" as the first-line ART regime in combination with 2 NRTIs.