Mortality remains elevated among Black vs. White adults receiving HIV care in the United States. We evaluated the effects of hypothetical clinic-based interventions on this mortality gap. We computed three-year mortality under observed treatment patterns among >40,000 Black and >30,000 White adults entering HIV care in the United States from 1996-2019. We then used inverse probability weights to impose hypothetical interventions, including immediate treatment and guideline-based follow-up. We considered two scenarios: “universal” delivery of interventions to all patients and “focused” delivery of interventions to Black patients while White patients continued to follow observed treatment patterns. Under observed treatment patterns, three-year mortality was 8% among White patients and 9% among Black patients, for a difference of 1 percentage point (95% CI: 0.5, 1.4). The difference was reduced to 0.5% under universal immediate treatment (-0.4, 1.3), and to 0.2% under universal immediate treatment combined with guideline-based follow-up (-1.0, 1.4). Under the focused delivery of both interventions to Black patients, the Black-White difference in three-year mortality was -1.4% (-2.3, -0.4). Clinical interventions, particularly those focused on enhancing the care of Black patients, could have significantly reduced the mortality gap between Black and White patients entering HIV care from 1996-2019.