As part of our ongoing chemical investigation of biologically active metabolites from marine fungi, three new compounds, p-hydroxyphenopyrrozin (1) and diketopiperazines (3, 4), have been isolated from the marine-derived fungus Chromocleista sp. In addition, the fungus gave the known compound phenopyrrozin (2), four known diketopiperazines (6-9), N-acetyltryptamine (10), and agathic acid (11). Another new diketopiperazine (5) was separated and identified as a decomposition product of 3 and 4. The structures of the new metabolites were determined on the basis of mass spectroscopy, NMR experiments, and derivatization methods. The absolute configuration of 1 was determined by X-ray crystallography studies.