Background:The impact of pre-antiretroviral treatment (ART) HIV-RNA on time to successful virological suppression and subsequent failure in HIV patients remains poorly investigated.Methods:We used the Swedish InfCareHIV database and the Danish HIV Cohort Study to evaluate impact of pre-ART HIV-RNA on primary virological suppression (HIV-RNA < 50 copies/ml) and risk of secondary virological failure (two consecutive HIV-RNA > 200 copies/ml or one >1000 copies/ml). The study included 3366 Swedish and 2050 Danish ART naive individuals who initiated ART in the period 2000-2018. We used Kaplan-Meier estimates and Cox regression analyses to estimate absolute risks and hazard ratios.Results:In both cohorts, more than 95% of patients with a pre-ART HIV-RNA <100 000 copies/ml obtained virological suppression within the first year after ART initiation contrasting 74% (Sweden) and 86% (Denmark) in those with HIV-RNA >1 000 000 copies/ml. Almost all patients obtained virological suppression after four years irrespective of pre-ART HIV-RNA. In contrast, we observed no substantial impact of pre-ART HIV-RNA on risk of virological failure once virological suppression was obtained.Conclusion:High pre-ART HIV-RNA is strongly associated with increased time to successful virological suppression, but pre-ART HIV-RNA has no impact on risk of subsequent virological failure.