AbstractBoth science and politics have been involved in the debate over ‘nuclear winter’. Political interests seem to have influenced the degree of scientific attention to the nuclear winter effect, some of the assumptions underlying the models developed to study it, and the criticisms made of it. Conversely, nuclear winter results have been used as tools to promote particular stands on nuclear policy-making.In all this, most scientists involved with the studies have tried to define science as separate from politics. The debate raises in acute form the contradiction involved in science allegedly being objective and apolitical while at the same time it is intermeshed with policy disputes.