A BSTRACT This article investigates how voters decide in referendums on European integration. More specifically, it analyses how political information influences voting behaviour. It argues that political information conditions the way in which people make decisions in referendums. The impact of political information is examined not only at the individual, but also at the contextual level. It is hypothesized that variations in the context of the referendum – the intensity of the campaign – produce differences in the way in which citizens act in referendums. As the intensity of the referendum campaign increases, more information is available to citizens and voters will rely more heavily on sophisticated criteria, such as attitudes and issue positions on the European Union (EU). While the informational context influences voting patterns, individuals also vary in their awareness of politics. It is argued that people with high levels of political awareness receive more information and consequently rely more on their own attitudes and less on elite cues when deciding. These theoretical propositions are tested by analysing survey data from EU referendums in Denmark, Ireland and Norway.