Mosaic plants of perilla were collected in Tokyo and Saitama prefecture. Virus particles detected in the diseased leaves were flexuous rods, about 13×760nm, with a helical symmetry of 3.4nm pitch. In ultrathin sections of the diseased leaves, the virus particles and cytoplasmic inclusions such as pinwheels and bundles were observed in the cytoplasm of virus-infected cells. By sap inoculation, the virus produced chlorotic local lesions on Chenopodium amaranticolor, C. quinoa, Gomphrena globosa, and Vicia faba, while it produced systemic mottling on Perilla frutescens var. acuta. The virus was also transmitted in a non-persistent manner by Myzus persicae (Sulz.). The virus was tentatively named perilla mottle virus.