A survey investigated risk judgements related to climate change. In order to understand which the important determinants of such risk judgements are, demographic factors and knowledge were assessed in a questionnaire answered by 621 Swedish residents. Demographic factors included gender, parenthood, type and level of education, age, and level of urbanization of the place of residence, while knowledge covered knowledge of state, causes, and consequences of climate change. Regression analyses showed that both cognitive risk judgements (of probability) of serious negative consequences and affective risk judgements (worry) were predicted by knowledge of causes and knowledge of consequences of climate change, in particular health consequences. Women were more worried than men but did not differ from men with respect to the cognitive risk judgements. (c) 2007 Elsevier Ltd. All rights reserved.