BACKGROUND: Disaster preparations usually focus on preventing injury and infectious disease. However, people with chronic disease and related conditions (CDRCs), including obstetric/gynecological conditions, may be vulnerable to disruptions caused by disasters. METHODS: We used surveillance data collected after Hurricane Katrina to characterize the burden of visits for CDRCs at emergency treatment facilities (eg, hospitals, disaster medical assistance teams, military aid stations). In 6 parishes in and around New Orleans, health care providers at 29 emergency treatment facilities completed a standardized questionnaire for injury and illness surveillance from September 8 through October 22, 2005. RESULTS: Of 21,673 health care visits, 58.0% were for illness (24.3% CDRCs, 75.7% non-CDRCs), 29.1% for injury, 7.2% for medication refills, and 5.7% for routine or follow-up care. The proportion of visits for CDRCs increased with age. Among men presenting with CDRCs, the most common illnesses were cardiovascular disease (36.8%), chronic lower-respiratory disease (12.3%), and diabetes/glucose abnormalities (7.7%). Among women presenting with CDRCs, the most common were cardiovascular disease (29.2%), obstetric/gynecological conditions (18.2%), and chronic lower-respiratory disease (12.0%). Subsequent hospitalization occurred among 28.7% of people presenting with CDRCs versus 10.9% of those with non-CDRCs and 3.8% of those with injury. CONCLUSIONS: Our data illustrate the importance of including CDRCs as a part of emergency response planning.