This study investigated adolescent responses to nuclear threat during intervals preceding and following the Chernobyl disaster. The Nuclear Threat Index was administered to 96 Israeli subjects two months prior to and two months following the disaster. In addition, they were tested with Rotter's Locus of Control Scale. The data results indicate that on the whole there were differences in scores between the two administrations, especially with respect to self-reported activity (behavioral subscales). Adolescents reported significantly more past nuclear-related activity before the accident as well as fewer anticipated activities after the accident. Adjusted for the preaccident score differences data reveal that after the accident younger adolescents reported less pessimism and more previous activity than the older adolescents. In addition, males reported more nuclear-related activity than females; younger males reported more past activity and less pessimism than older males; "external" males reported more activity than "internal" males. Discussion focuses on possible explanations for the results, on limitations of the investigation, and on implications for further research.