One new dihydrobenzofuran derivative, botryomaman (1), was isolated from the broth extract of the endophytic fungus Botryosphaeria mamane PSU-M76 along with six known compounds, 2,4-dimethoxy-6-pentylphenol, (R)-(-)-mellein, primin, cis-4-hydroxymellein, trans-4-hydroxymellein and 4,5-dihydroxy-2-hexenoic acid. The structures were assigned by spectroscopic methods. All compounds were tested for antibacterial activity against Staphylococcus aureus ATCC 25923 and methicillin-resistant S. aureus SK1. Primin showed the best activity against both strains with equal MIC values of 8 microg/ml.