OBJECTIVES: We investigated the prevalence of drug resistance mutations (DRMs) in individuals newly diagnosed with HIV-1 in Estonia in 2020 and 2022, and in Ukrainian war refugees living with HIV who arrived in Estonia in 2022. METHODS: HIV-1 genomic RNA was sequenced in protease-reverse transcriptase and integrase (IN) regions. DRMs were determined separately by Stanford University CPR Tool and HIVdb Program. REGA HIV-1 Subtyping Tool and phylogenetic analysis were used for subtyping. RESULTS: Both regions were successfully sequenced in 79 and 53 individuals in 2020 and 2022 populations, respectively. The DRM rates were 11.4% [95% CI, 5.3%-20.5%] in 2020 and 13.2% [95% CI 5.5%-25.3%] in 2022. There was a low percentage of resistance to IN strand transfer inhibitors: 3.8% [95% CI, 0.8-10.7] in 2020 and 1.9% [95% CI, 0.05-10.1] in 2022. Most Ukrainian war refugees had undetectable VL (57/88, 65%), were women (63%) and majority were infected with subtype A6 viruses. The overall DRM rate for Ukrainian population was 11.5%. CONCLUSIONS: Identifying HIV DRMs using HIVdb Program combined with CPR tools gives comprehensive overview of transmitted drug resistance. Resistance testing might be necessary before initiating antiretroviral therapy if the first-line treatment does not include PI or second-generation IN strand transfer inhibitors.