Species of the genus Phyllotreta Chevrolat in Japan and Taiwan are reviewed. Phyllotreta striolata (Fabricius) is redescribed based on Taiwanese specimens; P. chotanica Duvivier is recorded for the 1st time in Taiwan; and P. downesi insularis Heikertinger is raised to species level. Lectotypes and paratypes are designated for P. downesi insularis.