Sporobolomyces odorus produces gamma-decalactone and cis-6-dodecen-4-olide, substances which exhibit odors characteristic of peaches and lamb meat (mutton), respectively. The growth and production of gamma-decalactone by S. odorus in broth to which fatty acids or oils had been added were investigated. The addition of decanoic acid or dodecanoic acid to the culture reduced the growth and production of gamma-decalactone by S. odorus. Without affecting the growth, the presence of Miglyol oil reduced the yield, whereas the addition of castor oil enhanced the production of gamma-decalactone by S. odorus. The greatest enhancement, with a yield of 8.62 mg/l of gamma-decalactone, about six times that in the control broth, was noted when 3% castor oil was added after 24 h of cultivation. On the other hand, the fatty acids and oils tested either reduced or had no effect on the production of cis-6-dodecen-4-olide by S. odorus.