Poor compliance with medications is a growing concern in geriatric care and is increasingly more relevant among people living with HIV (PLWH) as they age. Our goal was to understand geriatric conditions associated with antiretroviral therapy (ART) nonadherence in a Medicare population of older PLWH. We analyzed Medicare data from PLWH aged 50 years or older who were continuously enrolled in fee-for-service Medicare from January 1, 2014 to June 30, 2015. Prevalent geriatric conditions (dementia, depression, falls, hip fracture, sensory deficits, osteoporosis, orthostatic hypotension, urinary incontinence, frailty) were identified in January 1, 2014-December 31, 2014. ART nonadherence was defined as <80% proportion of days covered (PDC) by at least two ART medications in January 1, 2015-June 30, 2015. We examined geriatric condition association with nonadherence using lowest Akaike Information Criterion multi-variate logistic models, controlling for age, sex, race, census region, substance use, Medicaid eligibility, and polypharmacy. Of 8778 PLWH, 23% ( = 2042) had <80% PDC. The average age was 60 years (standard deviation ±8), and >70% were males. In adjusted models, age was not associated with nonadherence, frailty status was the only geriatric condition associated with nonadherence [robust: reference, prefrail odds ratio (OR): 0.97, confidence interval (95% CI) 0.86-1.10, frail OR: 1.34 95% CI 1.11-1.61], and odds of nonadherence were lower for polypharmacy [OR: 0.48 (0.43-0.54)]. Our findings suggest that patient-centered care plans aimed at improving ART adherence among older PLWH would benefit from long-term surveillance; a deeper understanding of the role of frailty and polypharmacy, even at chronologically younger ages in PLWH.