© 2017 The Author(s). Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. Background Age-associated conditions are increasingly common among persons living with human immunodeficiency virus (HIV) (PLWH). A longitudinal investigation of their accrual is needed given their implications on clinical care complexity. We examined trends in the co-occurrence of age-associated conditions among PLWH receiving clinical care, and differences in their prevalence by demographic subgroup. Methods This cohort study was nested within the North American AIDS Cohort Collaboration on Research and Design. Participants from HIV outpatient clinics were antiretroviral therapy-exposed PLWH receiving clinical care (ie, ≥1 CD4 count) in the United States during 2000-2009. Multimorbidity was irreversible, defined as having ≥2: hypertension, diabetes mellitus, chronic kidney disease, hypercholesterolemia, end-stage liver disease, or non-AIDS-related cancer. Adjusted prevalence ratios (aPR) and 95% confidence intervals (CIs) comparing demographic subgroups were obtained by Poisson regression with robust error variance, using generalized estimating equations for repeated measures. Results Among 22969 adults, 79% were male, 36% were black, and the median baseline age was 40 years (interquartile range, 34-46 years). Between 2000 and 2009, multimorbidity prevalence increased from 8.2% to 22.4% (P trend <.001). Adjusting for age, this trend was still significant (P <.001). There was no difference by sex, but blacks were less likely than whites to have multimorbidity (aPR, 0.87; 95% CI,.77-.99). Multimorbidity was the highest among heterosexuals, relative to men who have sex with men (aPR, 1.16; 95% CI, 1.01-1.34). Hypertension and hypercholesterolemia most commonly co-occurred. Conclusions Multimorbidity prevalence has increased among PLWH. Comorbidity prevention and multisubspecialty management of increasingly complex healthcare needs will be vital to ensuring that they receive needed care.