Hydrangea macrophylla, commonly known as bigleaf hydrangea, is a popular landscape shrub native to East Asia. It is widely cultivated in China and the United States (Veerakone et al. 2012). Virus-like symptoms, including mild mottling and leaf curling, were observed on the leaves of H. macrophylla plants in a garden in Jeju, Korea in June 2022. Disease incidence was estimated at approximately 10% (32 of 330). Negative staining of leaf samples collected from ten symptomatic plants followed by transmission electron microscopy revealed the infestation of rigid-rod-shaped particles (about 300 × 18 nm), a characteristic feature of viruses in the genus Tobamovirus. Leaf samples from ten symptomatic and two asymptomatic plants were tested by DAS-ELISA using polyclonal antibodies (Agdia, Elkhart, IN, USA) against cucumber green mottle mosaic virus, pepper mild mottle virus (PMMoV), tobacco mosaic virus, and tomato mosaic virus. All infected samples showed significant affinity to the antibody against PMMoV. To ascertain the presence of PMMoV, RT-PCR was performed using total RNA extracted from ELISA-positive samples with PMMoV-specific primers to amplify a specific region of the coat protein-encoding gene (Zhou et al. 2021). The expected amplicon size of 682 bp was obtained from all samples. The amplicons were cloned into the pGEM-T vector (Promega, Madison, WI), and five clones were sequenced for each amplicon. The PMMoV sequences obtained from all five samples were found to be identical. A representative sequence was deposited in GenBank (LC731733, PMMoV-CNU-1). BLASTn analyses indicated that the nucleotide sequence shared 96.1 to 99.4% homology with other PMMoV isolates. Nicotiana benthamiana leaves were mechanically inoculated with the sap extracted from PMMoV-CNU-1-infected leaves. Mild mottling and leaf-curling symptoms were observed on N. benthamiana leaves at 18 days post-inoculation. RT-PCR and DNA sequencing confirmed the PMMoV infection. This is the first report of PMMoV in H. macrophylla in Korea.