BACKGROUND: 40-60% of people with HIV report experiencing loneliness, and 5-29% of PWH are frail (depending on the definition used). The risk of death in individuals who are frail and lonely, or frail and socially isolated has recently been estimated to be 1·8 times that in individuals who are not frail, lonely, or socially isolated. The aim of the present study was to determine the prevalence of loneliness, and other vulnerabilities related to ageing, in frail older adults with HIV. METHODS: We assessed frailty with the Clinical Frailty Scale (CFS) in a cross-sectional, convenience sample of people with HIV aged 50 years or older in Southern Alberta, Canada. All Southern Alberta Clinic patients aged 50 years or older who attended a virtual or in-person clinic visit between March and October, 2020, and who underwent frailty screening were included in the present analyses. Individuals scoring 4 or higher on the CFS then completed a structured questionnaire to provide information on additional co-factors, including loneliness (Three-item Loneliness Scale), falls, impaired gait and balance, polypharmacy, unintentional weight loss, food insecurity, and subjective cognitive concerns. Age, sex, nadir CD4 cell count, duration of known HIV infection, ethnicity, and risk category were evaluated for associations with frailty. We used t tests to compare means and Pearson χ tests to compare proportions. Patients gave written informed consent for use of data. The use of data was approved by the University of Calgary Conjoint Heath Research Ethics Board. FINDINGS: We assessed frailty in 292 older people with HIV. The mean age was 59 years (range 50-86 years) and 45 (16%) were women. On the basis of a score of 4 or greater on the CFS, 40 (14%) participants were identified as frail. Frail individuals tended to be older than those who were not frail (mean age 61·9 years, SD 8·5 versus 58·4 years, SD 6·3; t test difference 3·5, 95% CI 1·3-5·7; p=0·0011). However, there was no association between frailty status and sex, nadir CD4 cell count, duration of known HIV infection, or self-reported ethnicity. Frail individuals were more likely to report injection drug use as a component of their risk for acquisition than were non-frail individuals. Of the frail participants, 15 (42%) reported loneliness, 15 (42%) had fallen in the past year, and 18 (50%) reported impaired gait or balance. One-fifth (8) reported unintentional weight loss and 12 (33%) experienced food insecurity. Nearly 40% (14) reported subjective memory concerns. INTERPRETATION: In this sample of ageing people with HIV, frailty and loneliness were prevalent. Given the increased risk of death when frailty and loneliness are both present, upstream and targeted interventions are urgently needed. These might include measures to address loneliness, risk of falls, weight loss, food insecurity, and memory concerns. FUNDING: Canadian Foundation for Healthcare Improvement, Advancing Frailty Care in the Community.