Post-traumatic stress disorder (PTSD) is a common psychological outcome of any disaster. The purpose of this study was to examine the effects of PTSD on disease progression among HIV-infected persons in metropolitan New Orleans post-hurricane Katrina. One-year post-storm, a convenience sample of 145 HIV-infected patients who returned to care at the HIV Outpatient Program clinic in New Orleans were interviewed. Clinical factors pre and one and two years post-disaster were abstracted from medical records and compared by PTSD status. Of the 145 participants, 37.2% had PTSD. Those with PTSD were more likely than those without PTSD to have detectable plasma viral loads at both follow-up time points post-disaster and more likely to have CD4 cell counts <200/mm(3) two years post-disaster. They were also more likely to have had medication interruptions immediately post-disaster. Our findings corroborate the findings of others that PTSD accelerates HIV disease progression. Disaster planners should consider the special counseling and medication safeguards needs of HIV-infected persons.