Background: There is conflicting evidence about how HIV infection influences COVID-19. We compared the presentation characteristics and outcomes of people with and without HIV hospitalised with COVID-19 at 207 centres across the United Kingdom. Methods: We analysed data from people with laboratory confirmed or highly likely COVID-19 enrolled into the ISARIC CCP-UK study. The primary endpoint was day-28 mortality after presentation. We used Kaplan-Meier methods and Cox regression to describe the association with HIV status after adjustment for sex, ethnicity, age, indeterminate/probable hospital acquisition of COVID-19 (definite hospital acquisition excluded), presentation date, and presence/absence of ten comorbidities. We additionally adjusted for disease severity at presentation as defined by hypoxia/oxygen therapy. Findings: Among 47,539 patients, 115 (0·24%) had confirmed HIV-positive status and 103/115 (89·6%) had a record of antiretroviral therapy. At presentation, relative to the HIV-negative group, HIV-positive people were younger (median 55 versus 74 years; p<0·001), had a higher prevalence of obesity and moderate/severe liver disease, higher lymphocyte counts and C-reactive protein, and more systemic symptoms. The cumulative incidence of day-28 mortality was 25·2% in the HIV-positive group versus 32·1% in the HIV-negative group (p=0·12); however, stratification for age revealed a higher mortality among HIV-positive people aged below 60 years. The effect of HIV-positive status was confirmed in adjusted analyses (adjusted hazard ratio [HR] 1·49, 95% confidence interval [CI] 0·99-2·25; p=0·06). Following additional adjustment for disease severity at presentation, mortality was higher in HIV-positive people (adjusted HR 1·63; 95% CI 1·07-2·48; p=0·02). In the HIV-positive group, mortality was more common among those who were slightly older and among people with obesity and diabetes with complications. Interpretation: HIV-positive status may be associated with an increased risk of day-28 mortality following a COVID-19 related hospitalisation. Trial Registration: ISRCTN66726260 Funding Statement: NIHR, MRC, Wellcome Trust, Department for International Development, Bill and Melinda Gates Foundation. Declaration of Interests: AMG: Personal fees from Roche Pharma Research & Early Development (pRED), consulting honoraria from Gilead, Janssen, and ViiV Healthcare, and research funding from Roche pRED, Gilead, Janssen and ViiV Heathcare, outside of the work presented in this article. GV: research funding from ViiV Healthcare outside of the work presented in this article. CAS: personal fees from Gilead Sciences and ViiV Healthcare for participation in Data Safety and Monitoring Boards, membership of Advisory Boards and for preparation of educational materials, outside of the work presented in this article. MGS: grants from DHSC NIHR UK, MRC UK, and HPRU in Emerging and Zoonotic Infections during the conduct of the study; other from Integrum Scientific LLC (Greensboro, NC, US), outside the submitted work. The remaining authors declare no competing interests, no financial relationships with any organisations that might have an interest in the submitted work in the previous three years, and no other relationships or activities that could appear to have influenced the submitted work. Ethics Approval Statement: Ethical approval was given by the South Central - Oxford C Research Ethics Committee in England (Ref 13/SC/0149), the Scotland A Research Ethics Committee (Ref 20/SS/0028), and the WHO Ethics Review Committee (RPC571 and RPC572, 25 April 2013.