The article addresses the issue of the presence of false information on coronavirus in the Polish news media between January and September 2020. The research aimed to check the extent to which traditional media participate in disinformation processes during the pandemic. An attempt has also been made at explaining the reasons for the publication of fake news in these media. Sources of information that Poles use most often were examined: popular information portals, traditional media websites, and social media (Facebook and Twitter). The article analyses false information in both quantitative and qualitative terms. A total of 101 pieces of false information made available online were diagnosed, of which every fourth news item (25.74%) appeared in opinion-forming media (three most popular news portals and all traditional media were taken into account). The qualitative analysis shows that publishing false information in the opinion-forming media is the result of changes in the journalistic work environment (especially declining standards of work, a desire to attract the attention of the media audience and the pursuit of the media organisations’ own interests). However, this issue requires further research in editorial offices and among journalists.