Background: Post-traumatic stress disorder (PTSD) may be associated with chronic immune dysregulation and a proinflammatory state. Among HIV-infected individuals, PTSD is associated with greater morbidity and mortality, but the association with immune dysfunction has not been evaluated. This study explores the association between PTSD and selected markers of inflammation and immune activation in a cohort of HIV-infected, virally-suppressed individuals. Methods: HIV-infected adults who were virologically controlled on antiretroviral medications were recruited through a screening protocol for studies of HIV-related neurocognitive disorders. Each participant underwent blood draws, urine toxicology screen, and completed the Client Diagnostic Questionnaire, a semistructured psychiatric interview. Results: Of 114 eligible volunteers, 72 (63%) were male, 77 (68%) African American, and 34 (30%) participants met criteria for PTSD. Participants with PTSD were more likely to be current smokers (79%) than those without (60%) (p = 0.05). The PTSD cohort had significantly higher total white blood cell counts (5318 and 6404 cells/uL, p = 0.03), absolute neutrophil count (2767 and 3577 cells/uL, p = 0.02), CD8% (43 and 48, p = 0.05), and memory CD8% (70 and 78%, p = 0.04); lower naïve CD8% (30 and 22%, p = 0.04) and higher rate of high-sensitivity C-reactive protein >3 mg/L (29 and 20, p = 0.03). Discussion: A high prevalence of PTSD was identified in this cohort of HIV-infected adults who were virally suppressed. These results suggest that PTSD may be associated with immune dysregulation even among antiretroviral therapy-adherent HIV-infected individuals.