Simultaneous conflicting attitudes towards an object make both predicting and explaining behaviour a complex endeavour. This paper explores the hypothesis of social ambivalence (so called as well or approach-avoidance conflict) as a phenomenon influencing attitudes towards the environmental effects of the introduction of GMOs (Genetic Modified Organisms). If social ambivalence exists it would be suggestive of an interplay between rational models or behaviour and normative or moral models of behaviour. This paper provides some quantitative analysis based on a representative sample of the European Union, using unique data from the Eurobarometer 58.0 (2002) examining public perceptions of environmental risks. Our findings suggest that GMOs are perceived as having a non-neutral impact on the environmental and social life and that as hypothesized there is evidence of social ambivalence, which appears to be more significant when environmental effects of GM foods are taken into account. Consistently with the hypothesis of interplay between rational and normative models of behaviour, respondents perceive some risks while benefits are not perceived by the public and moral concerns regarding technologies being developed by international corporations are important. A specific type of social ambivalence is found, namely GMO are not accepted for Europeans but they are in less developed countries.