Teachers play an important role in enhancing the quality of environmental education in schools. For teaching to be effective, teacher-trainees should have a clear conception of the subject they are going to teach. Therefore, it is essential to assess pre-service teachers' conceptions. The aim of this study was to investigate pre-service teachers' understanding of environment. In the present study, the written responses given by teacher-trainees to an open-ended question as to what they understand by the term "environment" were analysed. Student teachers' understandings are juxtaposed and findings are discussed for environmental education.