IMPORTANCE: Home-based HIV testing is a frequently used strategy to increase awareness of HIV status in sub-Saharan Africa. However, with referral to health facilities, less than half of those who test HIV positive link to care and initiate antiretroviral therapy (ART). OBJECTIVE: To determine whether offering same-day home-based ART to patients with HIV improves linkage to care and viral suppression in a rural, high-prevalence setting in sub-Saharan Africa. DESIGN, SETTING, AND PARTICIPANTS: Open-label, 2-group, randomized clinical trial (February 22, 2016-September 17, 2017), involving 6 health care facilities in northern Lesotho. During home-based HIV testing in 6655 households from 60 rural villages and 17 urban areas, 278 individuals aged 18 years or older who tested HIV positive and were ART naive from 268 households consented and enrolled. Individuals from the same household were randomized into the same group. INTERVENTIONS: Participants were randomly assigned to be offered same-day home-based ART initiation (n = 138) and subsequent follow-up intervals of 1.5, 3, 6, 9, and 12 months after treatment initiation at the health facility or to receive usual care (n = 140) with referral to the nearest health facility for preparatory counseling followed by ART initiation and monthly follow-up visits thereafter. MAIN OUTCOMES AND MEASURES: Primary end points were rates of linkage to care within 3 months (presenting at the health facility within 90 days after the home visit) and viral suppression at 12 months, defined as a viral load of less than 100 copies/mL from 11 through 14 months after enrollment. RESULTS: Among 278 randomized individuals (median age, 39 years [interquartile range, 28.0-52.0]; 180 women [65.7%]), 274 (98.6%) were included in the analysis (137 in the same-day group and 137 in the usual care group). In the same-day group, 134 (97.8%) indicated readiness to start ART that day and 2 (1.5%) within the next few days and were given a 1-month supply of ART. At 3 months, 68.6% (94) in same-day group vs 43.1% (59) in usual care group had linked to care (absolute difference, 25.6%; 95% CI, 13.8% to 36.3%; P < .001). At 12 months, 50.4% (69) in the same-day group vs 34.3% (47) in usual care group achieved viral suppression (absolute difference, 16.0%; 4.4%-27.2%; P = .007). Two deaths (1.5%) were reported in the same-day group, none in usual care group. CONCLUSIONS AND RELEVANCE: Among adults in rural Lesotho, a setting of high HIV prevalence, offering same-day home-based ART initiation to individuals who tested positive during home-based HIV testing, compared with usual care and standard clinic referral, significantly increased linkage to care at 3 months and HIV viral suppression at 12 months. These findings support the practice of offering same-day ART initiation during home-based HIV testing. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT02692027.