The purpose of study is to determine candidate science teachers' knowledge levels towards environmental problems and also to reveal whether teacher candidates' knowledge levels show a difference according to gender. Environmental problems knowledge level scale which includes 30 items has been used as the data gathering tool. One of the results obtained in the research is that teacher candidates' knowledge levels towards environmental problems change according to the items in the scale. Another result obtained in the research is teacher candidates' point averages which have taken from the scale do not indicate a meaningful difference according to gender. (C) 2011 Elsevier Ltd.