BACKGROUND: Universal test-and-treat trials increased population-level virological suppression across trial sites in sub-Saharan Africa. We followed the ANRS 12249 TasP trial population for 6 years to determine whether the intervention had longer-term survival benefits. METHODS: The TasP trial was a cluster-randomised trial implemented in 22 communities in rural South Africa, from 2012’2016. Households were offered six-monthly home-based HIV testing. Immediate antiretroviral therapy (ART) was offered in trial clinics to all people living with HIV (PLHIV) in the intervention clusters and according to national guidelines in the control clusters. At trial end, individuals attending the intervention clinics were transferred to the public ART programme, with a ’treat-all’ strategy adopted in September 2016. Deaths during and two years after trial end were ascertained through annual demographic surveillance. Random effects Poisson regression was used to estimate rate ratios (RR) and 95%CI for the effect of trial arm on mortality among i) all PLHIV regardless of serostatus awareness, ii) PLHIV aware of their status, iii) those not on ART at entry to trial clinics. An interaction term between period and treatment arm was included, to allow the effect of trial arm to differ between periods. RESULTS: Amongst all PLHIV and those aware of their serostatus, there was no effect of immediate ART on mortality (Table). Among individuals who started ART during the trial, there was evidence that the intervention decreased mortality (aRR=0.69, 95%CI=0.45-1.04, p=0.08), although the effect was primarily during the trial (aRR=0.49, 95%CI=0.28-0.85, p=0.01), but not after the trial ended (aRR=1.15, 95%CI=0.59-2.21, p=0.69). CONCLUSIONS: The ’treat-all’ strategy resulted in a mortality benefit amongst individuals who started ART within the trial but not in all PLHIV over 6 years of follow-up. To achieve maximum benefit of immediate ART in South Africa, barriers to ART uptake and retention in care need to be addressed.