The Panel on Plant Health performed a pest categorisation of the spider mite Oligonychus perditus Pritchard and Baker (1955) (Acari, Tetranychidae), for the EU. O. perditus is a well-defined and distinguishable species, native to China, Japan, Korea and Taiwan, and recognised mainly as a pest of Juniperus spp., Chamaecyparis spp. and Platycladus spp. It is absent from the EU and is listed in Annex IIAI of Directive 2000/29/EC. Its host plants, Juniperus spp. and Chamaecyparis spp., are also listed in Annex III of Directive 2000/29/EC. Plants for planting, cut flowers and branches are considered as pathways for this pest, which is also able to disperse naturally with the wind, over rather short distances. O. perditus has repeatedly been intercepted in the EU but does not appear to have established, although a small population of O. perditus survived 8 years on a single imported plant in the Netherlands. As the host range of O. perditus coincides with that of the closely related cosmopolitan Oligonychus ununguis, which occurs in the EU, it is quite likely that the presence of O. perditus in the EU would cause little additional damage. Cultural control (sanitation and destruction of infested material) and chemical control (acaricides, e.g. abamectin) are the major control methods. All criteria assessed by EFSA for consideration as a potential quarantine pest are met, though there are some uncertainties regarding impacts. The species is presently absent from the EU, and thus, the criteria for consideration as a potential regulated non-quarantine pest are not met.