The clinical guidelines for acquired immunodeficiency syndrome (AIDS) in HIV-infected Koreans recommend routine HIV drug resistance testing for patients undergoing their first highly active antiretroviral therapy or considering a change in medication after 2018. Herein, the trends in HIV-1 subtypes and drug resistance were assessed from 2017 to 2022 by retrospectively analyzing 2,107 HIV-1-infected patients’ data. The Stanford HIV Drug Resistance Database was used to analyze each patient’s HIV-1 polymerase ( pol) gene sequences. Subtype B infections were predominant in the study population (75.7%). Meanwhile, CRF01_AE was the most prevalent non-B subtype and increased from 58.4% to 73.7% during the study period. Overall, all types of drug resistance mutations (DRM) were detected in 34.7% of the HIV-1 pol sequences. The prevalence of DRMs and high-level resistance mutations decreased from 39.4% to 31.6% and 16.7% to 7.7%, respectively. The prevalence of DRM was higher in patients treated with antiretroviral therapy (ART). These findings indicate that the prevalence of non-B subtype HIV infection has increased rapidly in South Korea, and the overall prevalence of DRMs decreased between 2017 and 2022. Additionally, since DRM is high in ART-treated patients, routine standard genotypic resistance testing surveillance is important before and after the treatment.