Three new sterigmatocystin derivatives, oxisterigmatocystin A (1), oxisterigmatocystin B (2) and oxisterigmatocystin C (3), together with one known compound, 5-methoxysterigmatocystin (4), were isolated from the deep-sea-derived fungus Aspergillus versicolor. The structures of the new compounds were elucidated by spectroscopic methods. The cytotoxicities of compounds 1-4 were evaluated against the A-549 and HL-60 cell lines. Compound 4 exhibited moderate cytotoxicities against the A-549 and HL-60 cell lines with IC(50) value of 3.86 and 5.32 μM, respectively.