The aim of this study is to analyze the high school students' opinions on the benefits and harms of nuclear energy in terms of environmental values. This study is a descriptive field research. The study was carried out with the participation of 176 high school students. In order to collect data, an assessment tool which consists of open-ended questions and 3-point Likert type questions was used. The data were analyzed through the content analysis method. After the study, 95.45% of the students expressed that their knowledge levels about nuclear energy were inadequate, and 52.84% of the students considered nuclear energy to be harmful. Moreover, the students match the issue of nuclear power with the issue of nuclear power plants. On the other hand, the students stated that nuclear energy primarily calls radiation and the increase in cancer incidences to mind. © 2010 Elsevier Ltd. All rights reserved.