ABSTRACTA fourteen hour exposure to sunlight destroys about 90 and 77% aflatoxin B1added to groundnut flakes with and without fat whereas only about 50% of the toxin is destroyed when present as a natural contaminant. Treating the groundnut flakes with 20% urea and 2% soybean flour (a source of urease) at 50% moisture would bring about 70% destruction of aflatoxin B1; In large scale trials, destruction was about 85%. Treatment with urea does not bring down the PER value of the material, which is 1.5 after treatment as against 1.6 in the untreated groundnuts.