The ethyl acetate-soluble fraction from a methanol extract of Ferula foetida has afforded six new sulfide derivatives, (E)-3-methylsulfinyl-2-propenyl sec-butyl disulfide (foetisulfide A) (1), (Z)-3-methylsulfinyloxy-2-propenyl sec-butyl disulfide (foetisulfide B) (2), (E)-3-methylsulfinyloxy-2-propenyl sec-butyl disulfide (foetisulfide C) (3), bis(3-methylthio-2E-propenyl) disulfide (foetisulfide D) (4), 3,4,5-trimethyl-2-thiophenecarboxylic acid (foetithiophene A) (5), 3,4,5-trimethyl-2-(methylsulfinyloxymethyl)thiophene (foetithiophene B) (6), along with six known compounds. The structures of 1-6 were established on the basis of spectroscopic studies, with the elucidation of 5 confirmed by single-crystal X-ray crystallography.