BACKGROUND Anemia is a known risk factor for clinical failure following antiretroviral therapy (ART). Notably, anemia and inflammation are interrelated, and recent studies have associated elevated C-reactive protein (CRP), an inflammation marker, with adverse human immunodeficiency virus (HIV) treatment outcomes, yet their joint effect is not known. The objective of this study was to assess prevalence and risk factors of anemia in HIV infection and to determine whether anemia and elevated CRP jointly predict clinical failure post-ART. METHODS A case-cohort study (N = 470 [236 cases, 234 controls]) was nested within a multinational randomized trial of ART efficacy (Prospective Evaluation of Antiretrovirals in Resource Limited Settings [PEARLS]). Cases were incident World Health Organization stage 3, 4, or death by 96 weeks of ART treatment (clinical failure). Multivariable logistic regression was used to determine risk factors for pre-ART (baseline) anemia (females: hemoglobin