Initiating antiretroviral therapy (ART) as early as the day of HIV diagnosis is a strategy of increasing global interest to control the HIV epidemic and optimize the health of people living with HIV (PLWH). No detrimental effects of rapid‐start ART have been identified in randomized controlled trials undertaken in low‐ or middle‐income countries, or in cohort studies performed in high‐income countries. Rapid‐start ART may be a key approach in reaching the 2020 Joint United Nations Programme on HIV/AIDS goal of 90% of all PLWH knowing their status, 90% of those diagnosed receiving sustained ART, and 90% of those receiving ART achieving viral suppression; it may also be important for achieving the suggested fourth "90%" goal: improving health‐related quality‐of‐life in PLWH. Presently there is insufficient broad evidence for guidelines to recommend universal test‐and‐treat strategies for all people, in all settings, at HIV diagnosis; consequently, there is a pressing need to conduct high‐quality studies that investigate immediate ART initiation. This article evaluates global evidence regarding rapid‐start ART, including same‐day start, with particular focus on the implementation of this strategy in high‐income countries. [ABSTRACT FROM AUTHOR]