The Panel on Plant Health performed a pest categorisation of Septoria malagutii, the causal agent of annular leaf spot of potato, for the EU. The pest is a well‐defined fungal species and reliable methods exist for its detection and identification. S. malagutii is present in Bolivia, Ecuador, Peru and Venezuela. The pest is not known to occur in the EU and is listed as Septoria lycopersici var. malagutii in Annex IAI of Directive 2000/29/EC, meaning its introduction into the EU is prohibited. The major cultivated host is Solanum tuberosum (potato), but other Solanum species including wild solanaceous plants are also affected. All hosts and pathways of entry of the pest into the EU are currently regulated. Host availability and climate matching suggest that S. malagutii could establish in parts of the EU and further spread mainly by human‐assisted means. The pest affects leaves, stems and petioles of potato plants (but not the underground parts, including tubers) causing lesions, leaf necrosis and premature defoliation. In some infested areas, the disease has been reported to cause almost complete crop loss with favourable weather conditions and susceptible potato cultivars. The introduction of the pest into the EU would potentially cause impacts to potato production. The main uncertainties concern the host range, the maximum period the pest survives on host debris in soil, the maximum distance over which conidia of the pest could be dispersed by wind‐driven rain and the magnitude of potential impacts to the EU. S. malagutii meets all the criteria assessed by EFSA for consideration as potential Union quarantine pest. The criteria for considering S. malagutii as a potential Union regulated non‐quarantine pest are not met, since the pest is not known to occur in the EU.