In the present work the occurrence of aflatoxin in peanut (Arachis hypagaea L.) in the region of Santa Adélia, S.P., was investigated in three Stages, from harvest to industrialization: a) by the time the grower sells it to the oil mill: Epochs I and II; b) during its storage prior to milling: Epochs III and IV and c) after oil extration (peanut flour) : Epochs V and VI. In each Stage two collections of 10 samples each, were made in a total of 40 samples of peanuts and 20 samples of peanut flour. From the results the following conclusions could be drawn: 1) all samples, except one, were toxic; 2) the toxicity level, in terms of aflatoxin B , was hight, for 55% of the samples were in the category "High" and 31.6% in the category "Very High"; 3) the levels of aflatoxin were higher in Stages 1 and 2 (peanuts), decreasing in Stage 3 (peanut four); 4) five samples were excessively toxic with more than 10.00 ppm; 5) the aflatoxin is already present in peanuts when the grower take it to the oil mill, but it was not possible to detect, in this region, the influence of storage.