In searching for new insecticidal compounds from soil microorganisms, strains of streptomyces species showed insecticidal activities on Musca domestica and Bombyx mori were selected. Compounds Ⅰ-Ⅳ, which were isolated from the metabolites of no. 46 strain, were identified as piericidin C₁, C₂, C₃ and D₁, respectively by UV and NMR data analyses.