The proportion of people living with HIV (PLWH) in need of antiretroviral therapy (ART) is growing rapidly in Russia. Successful treatment outcomes reduces disease progression and contributes to HIV epidemic control. We conducted a pilot study following 100 PLWH newly found eligible for ART in St. Petersburg, Russia. We determined the proportion of PLWH who initiated ART, remained in treatment, and achieved an undetectable VL during 6-month follow up. Semi-structured interviews were conducted prior the initiation of ART and progress along the cascade was assessed through medical chart review. Individual characteristics associated with successful ART outcomes were assessed as part of efforts to generate hypotheses. Almost all (96%) participants initiated ART, full retention was demonstrated by 80%, among whom 71% achieved undetectable VL. Optimal retention was associated with older age and higher education (p < 0.05). There was no significant difference in ART outcomes between those who used illicit drugs and those had not. Interventions to improve treatment effectiveness should emphasize that initiation, optimal retention and achieving an undetectable VL are independent of drug abuse status. However, our pilot study highlights the need for the further research in the examining links between individual and structural factors and ART effectiveness.