During a program of general screening of extracts from various entomogenous fungi, the extract obtained from one of the strains of Metarhizium anisopliae (ARSEF No. 1095) showed consistent insecticidal activity when tested against a range of insects. In subsequent bioassay-guided chemical investigations, 10 different destruxins were isolated from the active fractions. A simple protocol was developed for the separation of neutral destruxins by a combination of flash silica gel chromatography and reverse phase h.p.l.c. The structures were assigned by chemical and spectroscopic means. Complete 1H and 13C n.m.r. assignments of the representative destruxins (A and B) were accomplished using different 1D and 2D n.m.r. techniques and this information was subsequently used in the structural elucidation of related compounds and in the complete assignment of their n.m.r. spectra. In this communication we report details of the isolation and characterization of these destruxins, including two new compounds, destruxin E2 and the chlorohydrin. Bioassay-guided fractionation of the culture broth of Metarhizium anisopliae resulted in the isolation of 10 insecticidal cyclodepsipeptides-the destruxins, including two new compounds, destruxin E2 and chlorohydrin. Complete 1H and 13C n.m.r. assignments for the major destruxins A and B by various 1D and 2D n.m.r. techniques provided a basis for identification and spectral assignments of other destruxins.