From August to October of both 2012 and 2013, powdery mildew was observed on white-fruited creeping cucumber(Melothria japonica [Thunb.] Maxim.) at Jinju, Korea. White mycelial colonies were observed on leaves and petioles. Lesions of severe infections were discolored or brown. In the present study, the morphological features of the anamorphic and teleomorphic reproductive stages of the fungus were studied. To complete the fungal identification, the sequence of the internal transcribed spacer region of a ribosomal RNA(ITS rRNA) gene was determined. Based on morphological characteristics and analysis of the ITS rRNA gene, the fungus causing the powdery mildew symptoms was identified as Podosphaera fusca. Although the host range of powdery mildew caused by P. fusca has been previously described, no full description and illustration of the infection, including symptoms and signs on white-fruited creeping cucumber, has yet appeared. To the best of our knowledge, this is the first full description of powdery mildew on white-fruited creeping cucumber, featuring molecular identification, symptoms, and signs.