New insecticidal antibiotics designated hydroxyfungerins A and B were isolated from the culture broth of a fungal strain Metarhizium sp. FKI-1079 together with a known compound, fungerin. The structures of hydroxyfungerins A and B were elucidated by spectroscopic studies including various NMR experiments. Hydroxyfungerins A and B showed growth inhibitory activity against brine shrimps, Artemia salina.