Domoic acid is the toxin responsible for incidents of amnesic shellfish poisoning. A rapid extraction and cleanup for the liquid chromatographic determination of domoic acid in unsalted seafood is reported. The method uses a single-step extraction with 50% aqueous methanol and a selective cleanup and preconcentration with strong-anion exchange, solid-phase extraction. Determination is performed by liquid chromatography with ultraviolet absorbance detection. The detection limit was 20–30 ng/g. Recoveries of 93% were achieved from 0.2 to 20 μg/g in mussel tissues. The method gave a precision of less than 3% for concentrations greater than 2 μg/g and less than 6% at 0.2 μg/g. A linear dynamic range of 104 can be achieved. The method was successfully applied to a variety of seafood products, including mussels, razor clams, crabs, and anchovies.