This study aims to determine misconceptions of pre-service teachers studying in the last grade of chemistry and biology departments about the greenhouse effect. The 36 item survey, developed by Boyes et al. was subjected to 52 pre-service teachers in the last grades studying in chemistry and biology departments through the survey model. The collected data were analysed by means of SPSS in percent (%) and in frequency (f). The results showed that the pre-service teachers have some misconceptions about what increases the greenhouse effect, the problems stemming from the increase in the greenhouse effect and what should be done to decrease the greenhouse effect. Besides, according to the results of Mann Whitney U - test, there is not a statistically meaningful difference between the pre-service teachers of chemistry and biology in terms of their conceptual knowledge [U = 271.000; p > .05]. (C) 2011 Published by Elsevier Ltd.