Two novel reduced benzo[j]fluoranthene derivatives, hypoxylonols A (3-ethoxy-1,4,9-trihydroxy-1,2,3,6b-tetrahydrobenzo[j]fluoranthen-8(7H)-one) (1) and B (3-methoxy-1,4,9-trihydroxy-1,2,3,6b-tetrahydrobenzo[j]fluoranthen-8(7H)-one) (2), were isolated from the fruiting bodies of the mushroom Hypoxylon truncatum. The structures of these compounds were established on the basis of 1D and 2D NMR spectroscopic data.