The EFSA Plant Health Panel performed a pest categorisation of Coleosporium eupatorii Arthur ex Cummins, a clearly defined heteroecious fungus of the family Coleosporiaceae, causing rust diseases on five-needle Pinus spp. (aecial hosts) and on several genera of the Asteraceae family (telial hosts), such as Eupatorium spp. and Stevia spp. C. eupatorii is reported from Asia as well as North, Central and South America. It is not known to occur in the EU. The pathogen is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072 and has not been intercepted in the EU. The pathogen can be detected on its host plants by DNA sequencing. The main pathway for the entry of C. eupatorii into the EU is host plants for planting, other than seeds. In the EU, there is availability of aecial host plants, with Pinus peuce, P. strobus and P. cembra being the most important ones. There is a key uncertainty about whether European Eupatorium species (specifically E. cannabinum) are hosts of C. eupatorii and thus the ability of the pathogen to complete its life cycle, establish and spread in the EU. C. eupatorii could potentially spread within the EU by both natural and human-assisted means. The introduction of C. eupatorii into the EU is expected to have an economic and environmental impact. Phytosanitary measures are available to prevent the introduction and spread of the pathogen in the EU. C. eupatorii satisfies the criteria that are within the remit of EFSA to assess for this species to be regarded as potential Union quarantine pest.