Two chalcones, xanthoangelol (I) and 4-hydroxyderricin (II), isolated from the root of Angelica keiskei KOIDZUMI (Umbelliferae) showed antibacterial activity against gram-positive pathogenic bacteria. The activity of I on Micrococcus luteus IFO-12708 (minimum inhibitory concentration (MIC), 0.76 μg/ml) was the same potency as that of gentamicin, which is used as a standard. Although the activity of both chalcones on plant-pathogenic bacteria was lower than that of streptomycin sulfate, used as a positive control, they also exhibited growth-inhibitory effects. The antibacterial activity of I isolated from Angelica keiskei KOIDZUMI is being reported here for the first time. The growth-inhibitory effect of II on plant-pathogenic bacteria is also reported for the first time in this paper.