A joint Interlaboratory study of a rapid, solvent-efficient liquid chromatographic method for determination of ochratoxin A (OTA) in barley, corn, and pork kidney tissue was conducted by AOAC, the International Union of Pure and Applied Chemistry, and the Nordic Committee on Food Analysis In 16 laboratories in Europe, Canada, and the United States. OTA was added to barley and corn at 10,20, and 50 ng/g and to kidney at 5,10, and 20 ng/g. Duplicate test portions were prepared at 20 ng/g for corn and barley and 10 ng/g for kidney. Mean recoveries of OTA ranged from 53 to 97%. Within-laboratory relative standard deviations were 7.9,20.1, and 15.7% for barley, corn, and kidney tissue, respectively. Between-laboratories relative standard deviations were 20.7-31.7% for all concentrations of OTA In barley and corn and 68.0,41.8, and 32.7% for OTA concentrations of 5,10, and 20 ng/g, respectively, In kidney. OTA Identity was confirmed by methyl ester derivatization followed by liquid chromatography. The method has been adopted first action by AOAC as quantitative at the levels tested for OTA determination In corn and barley.