ABSTRACT: INTRODUCTION:Many African countries have had at least two years' experience with universal treatment eligibility for HIV. The literature contains few descriptions, though, of populations starting treatment since adoption of universal eligibility. Using baseline data from a clinical trial of same-day ART initiation, we describe the populations presenting for HIV testing or care at study clinics in Kenya and South Africa in 2017-18, during the era of same-day initiation. METHODS:The Simplified Algorithm for Treatment Eligibility (SLATE) trials in Kenya (SLATE I) and South Africa (SLATE II) were multicenter, non-blinded, individually randomized, pragmatic trials evaluating simple, standardized algorithms to determine eligibility for same-day initiation of ART without relying on laboratory results, point of care tests or multiple clinic visits. In Kenya, enrolment occurred during July 2017 to April 2018. In South Africa, enrolment occurred during March to September 2018. We describe demographic, socioeconomic and clinical characteristics of patients randomized to the same-day initiation arm for both studies. RESULTS AND DISCUSSION:A total of 240 and 296 participants were enrolled in Kenya and South Africa. The majority were female (59% and 64% respectively), with a median age of 35 years. In both countries, most subjects were newly diagnosed with HIV on the day of enrolment (62%, 55%), believed they already had adequate knowledge to begin ART (78%, 68%), and preferred to start ART immediately (same-day) (98% in both countries). About 40% of all patients had at least one symptom related to tuberculosis (cough, fever, night sweats, weight loss) and/or cryptococcal meningitis (continuous headache). More than a third of patients (37%, 36%) presented with advanced disease (CD4 <200 cells/mm3 ), a fifth presented with very advanced disease (CD4 < 100), and approximately 1 in 20 presented with very advanced disease and were asymptomatic. CONCLUSIONS:Despite >2 years of universal eligibility for ART in Kenya and South Africa, in 2017-2018 more than half of HIV-positive patients presenting at public sector clinics were not yet aware of their status, and more than a third presented for care with advanced HIV disease. These proportions remain similar to those observed before the introduction of universal eligibility.