Effective 31 December 1990, the sale of wild-caught red drum was banned in the state of Texas. Practical enforcement of this legislation required the use of a technique that could unambiguously discriminate between wild and farm-raised fish. Fatty acid profiles were established for wild red drum from 4 major Texas bay systems as well as from 2 aquaculture ventures to determine if this technique could be a useful enforcement tool. Results indicate that fatty acid compositions, especially levels of linoleic acid (18:2n-6) and arachidonic acid (20:4n-6), can be useful to distinguish between wild and cultured red drum. The ability to determine the origin of fish greatly enhances the enforcement of legislation designed to protect fisheries resources.