The chemical composition of the essential oils obtained by hydrodistillation from the aerial parts of Psoralea mutisii (Miq.) Standl (Leguminoseae) was elucidated by a combination of GC and GC-MS analyses. Twenty nine compounds were identified representing 89.4% of the total oil composition. The major components were bakuchiol (18.9%), psoralen (16.7%), angelicin (12.6%), germacrene D (6.8%) and β-caryophyllene (5.4%). The major volatiles released by β-glucosidase treatment of the aqueous plant residue were α-pinene (17.8%), germacrene D (9.8%) and tricyclene (5.6%). The oil exhibited significant antibacterial activity against Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, and Pseudomonas aeruginosa, while the β-glucosidase-liberated fraction was inactive.