An analysis of the risk to the countries of the European Union from a possible introduction of Bursaphelenchus xylophilus and its vectors in the genus Monochamus is performed by assembling relevant biological, climatic and commercial information. The risks presented by different trade pathways are assessed and phytosanitary measures to reduce the risks are proposed. The conclusion of the PRA, based on EPPO PRA guideline no. 1, is that these pests present a serious risk to European coniferous forests.