Lonicera vidalii Franch. & Sav. (family Caprifoliaceae) is a native tree in Korea and Japan. It is a rare deciduous tree of the forest community, mainly occurring in the southern part of Korea. In September 2017, leaf spots on trees, typical symptoms caused by cercosporoid fungi, were observed in Hongneung Arboretum, Seoul, Korea (37°35′37″N, 127°02′38″E). Initial symptoms presented as orbicular to irregular, pale- to dark-brown leaf spots typically 0.2 to 0.9 cm in diameter, which in some cases merged to form larger blotches across the surface of mature leaves. At infection sites, septate, branched, hyaline to pale brown, smooth, and 2 to 2.5 μm wide hyphae of the fungus were seen emerging through the stomata at the adaxial leaf side. Stromata were large and well-developed, globular, olivaceous brown, 30 to 50 µm in diameter, and emerging through stomatal openings. Conidiophores were aggregated in loose to dense fascicles through stomatal openings, subcylindrical, proliferating sympodially, straight to slightly geniculate, one- to four-septate, 15 to 53 × 3.5 to 5.5 μm, and smooth. Conidiogenous cells were terminal, cylindrical, proliferating sympodially, and 12.5 to 27 × 3.5 to 5.5 μm. Conidia were solitary, guttulate cylindrical to narrowly obclavate, straight to mildly curved, obtuse to rounded at the apex, one- to four-septate, variable in length, and 19 to 97 × 2 to 4 μm. Three monoconidial isolates were deposited in the culture collection (CDH) of the National Institute of Forest Science, Korea (CDH2017-15 to CDH2017-17). To ensure the identity of the fungus, genomic DNA was extracted, and sequence comparisons were made based on the partial nucleotide sequences of internal transcribed spacer (ITS) rDNA, translation elongation factor-1 alpha (EF-1α), actin, and RNA polymerase II second largest subunit (rpb2), using the respective primer pairs ITS1/ITS4, EF1-728F/EF1-986R, ACT-512F/ACT-783R, and RPB2-5f2/fRPB2-7cR (Nakashima et al. 2016). The sequences obtained were deposited in GenBank (MG712852 to MG712854, MG712861 to MG712863, MG712858 to MG712860, and MG930772 to MG930774, respectively). For a phylogenetic analysis, sequences from different gene regions (ITS, EF-1α, actin, and rpb2) obtained from GenBank were aligned, concatenated, and analyzed as a single dataset based on a maximum likelihood analysis. This Korean cercosporoid fungus was positioned in a clearly distinct lineage, provisionally representing an undetermined species of Pseudocercospora, which is closest to Pseudocercospora stephanandrae (Tak. Kobay. & H. Horie) C. Nakash. & Tak. Kobay., MUCC 914 (NR 111469 in ITS, GU384526 in EF-1α, GU320516 in actin, and KX462658 in rpb2). Sequence comparisons revealed that this Korean pathogen differed from P. stephanandrae at 4 of 477 characters (∼1.0%) in the ITS, 3 of 294 (∼1.0%) in the EF-1α, 4 of 190 (∼2.1%) in the actin, and 43 of 686 (∼6.3%) in the rpb2 sequences. In addition, this Korean pathogen is morphologically distinct from P. stephanandrae by having larger stromata as well as longer conidiophores and conidial size (Nakashima and Kobayashi 2000). Based on morphology and molecular analyses, the fungus was tentatively identified as Pseudocercospora sp. (Guo and Hsieh 1995; Nakashima et al. 2016). Pathogenicity was demonstrated by hyphal suspensions from 15-day-old cultures onto leaflets of L. vidalii and then maintaining them in a growth chamber (22°C and 80% relative humidity). Controls were treated with sterile water. Distinct leaf spot symptoms on the inoculated leaflets were developed, and the controls remained symptomless. The pathogen, recovered from symptomatic leaflets, was morphologically identical to those observed in the field. Lonicera-Pseudocercospora associations were recorded in China, Japan, Taiwan, Korea, New Zealand, and Brazil. However, the leaf spot infection associated with Pseudocercospora sp. on L. vidalii has not been recorded worldwide (Farr and Rossman 2017). This is the first report of leaf spot caused by Pseudocercospora sp. on L. vidalii globally as well as in Korea. The disease poses a threat to ornamental plantings and naturally growing plants of Lonicera spp. in Korea.