Internet, new technologies and social networks have changed the consumption and dissemination of information. The world is witnessing the proliferation of so-called false news, especially since the beginning of 2020, when COVID-19 became the main issue on the global agenda. Alleged government actions, remedies, advice, etc., are the cause of a multitude of messages that are often false. Through surveys (1115 responses were obtained) and a review of the literature, we explore how the proliferation of COVID-19’s false news affects and impacts public opinion in Spain. We also examine how citizens are being informed about the pandemic, identify the main channels of communication used and discover the impact of misinformation. The main conclusions are that, in Spain, citizens are interested in information related to the coronavirus, but there is a lack of media credibility and reliability; the social networks and instant messaging are considered the channels that transmit the greatest amount of false news.