INTRODUCTION: HPTN 071 (PopART) is a three-arm community randomized trial in Zambia and South Africa evaluating the impact of a combination HIV prevention package, including universal test and treat (UTT), on HIV incidence. This nested study examined factors associated with timely linkage-to-care and ART initiation (TLA) (i.e. within six-months of referral) in the context of UTT within the intervention communities of the HPTN 071 (PopART) trial. METHODS: Of the 7572 individuals identified as persons living with HIV (PLWH) (and not on antiretroviral treatment (ART)) during the first year of the PopART intervention provided by Community HIV-care Providers (CHiPs) through door-to-door household visits, individuals who achieved TLA (controls) and those who did not (cases), stratified by gender and community, were randomly selected to be re-contacted for interview. Standardized questionnaires were administered to explore factors potentially associated with TLA, including demographic and behavioural characteristics, and participants' opinions on HIV and related services. Odds ratios comparing cases and controls were estimated using a multi-variable logistic regression. RESULTS: Data from 705 participants (333 cases/372 controls) were analysed. There were negligible differences between cases and controls by demographic characteristics including age, marital or socio-economic position. Prior familiarity with the CHiPs encouraged TLA (aOR of being a case: 0.58, 95% CI: 0.39 to 0.86, p = 0.006). Participants who found clinics overcrowded (aOR: 1.51, 95% CI: 1.08 to 2.12, p = 0.006) or opening hours inconvenient (aOR: 1.63, 95% CI: 1.06 to 2.51, p = 0.02) were less likely to achieve TLA, as were those expressing stronger feelings of shame about having HIV (ptrend = 0.007). Expressing "not feeling ready" (aOR: 2.75, 95% CI: 1.89 to 4.01, p < 0.001) and preferring to wait until they felt sick (aOR: 2.00, 95% CI: 1.27 to 3.14, p = 0.02) were similarly indicative of being a case. Worrying about being seen in the clinic or about how staff treated patients was not associated with TLA. While the association was not strong, we found that the greater the number of self-reported lifetime sexual partners the more likely participants were to achieve TLA (ptrend = 0.06). There was some evidence that participants with HIV-positive partners on ART were less likely to be cases (aOR: 0.75, 95% CI: 0.53 to 1.06, p = 0.07). DISCUSSION: The lack of socio-demographic differences between cases and controls is encouraging for a "universal" intervention that seeks to ensure high coverage across whole communities. Making clinics more "patient-friendly" could enhance treatment uptake further. The finding that those with higher risk behaviour are more actively engaging with UTT holds promise for treatment-as-prevention.