One of the key democratic functions of the media is to provide people with the kind of information they need to be free and self-governing. This is equally important when it comes to the coverage of opinion polls. Thus far, there is however only limited research on the quality of the media’s coverage of opinion polls, including factors that might help to explain variation in the quality of opinion poll coverage. Against this background, the purpose of this study is (1) to investigate the extent to which news media take statistical uncertainties into account when covering opinion polls and making causal interpretations based on opinion polls, and (2) to explore some factors that might help to explain variation in the quality of opinion poll coverage. Among other things, the results show that journalists very often fail to take statistical uncertainties into account and that they, in about half of the cases, provide explanations for changes that are within the margin of error. The results also show that the quality of opinion poll coverage varies between different types of media organizations and between election campaigns and off-election periods.