This study concentrates on the area of environmental education and environmental attitudes and behaviour. The main purpose of the study is to pay attention to the environmental knowledge of students as well as to explore the environmental concerns, attitudes and behaviour of Finnish secondary level students in order to be able to educate environmentally concerned and aware students through developing teacher training. As a comparison the environmental knowledge, attitudes and self-reported behaviour of students of one German school were studied. Promoting environmental awareness as well as an environmentally responsible lifestyle can only be realised through information, and therefore students'' main information sources on certain general environmental issues were studied and analysed. The changes during the years 1994 to 2000 were examined.