A liquid chromatographic procedure has been developed for analysis of cyclopiazonic acid in peanuts. The chromatographic system specifies a C18 or C8 column loaded with 4-dodecyldiethylenetriamine and an aqueous mobile phase containing 4-dodecyldiethylenetriamine, zinc acetate, ammonium acetate, 2-propanol, and acetonitrile. Cyclopiazonic acid was extracted from peanuts with methanol-chloroform (20 + 80), partitioned into aqueous sodium bicarbonate, acidified, and back-extracted into dichloromethane. The limit of detection (280 nm UV) was approximately 4 ng and detector response was linear to at least 1 microgram pure cyclopiazonic acid. The recovery of cyclopiazonic acid from peanuts spiked at 68.9, 210, and 955 micrograms/kg was 85.9% (12.86% CV), 72.9% (6.43% CV), and 81.4% (0.40% CV), respectively. Calculation of the chromatographic peak parameters based on the exponentially modified Gaussian model indicated that the C18 column produced less peak skewing than did the C8 column.