Objectives: This study investigates the effect of Hurricane Katrina on adolescent feelings of social isolation. Much anecdotal evidence suggests that individuals who continued to reside in New Orleans after Hurricane Katrina struck felt isolated from the rest of the country. Based on Durkheim's concept of anomie, we suggest that adolescents in New Orleans (and the Gulf region) may experience social isolation as a result of the hurricane. Methods: We test this hypothesis with data from the Adolescent Substance Abuse Prevention Study, a multisite longitudinal study of adolescents in six cities around the United States. Results: We find that students in New Orleans are no different from students in the other five cities in their level of social isolation prior to the hurricane. In contrast, our posthurricane survey reveals significant differences between New Orleans (and Gulf region) students and students in the other five (comparison) cities in social isolation. Conclusions: Our findings lend contemporary support to the concept of anomie and suggest the importance of mental health interventions for adolescents immediately following a natural disaster.