Aflatoxin contamination is one of the important problems on peanuts and their products. The aim of the study was to detect aflatoxin occurrence and critical periods of toxin production on peanuts collected in different periods. The study was carried out in the years of 2010 and 2011 at experimental and different research areas of Osmaniye. Peanut kernels toxin analysis was performed at four distinct periods during the harvesting process: harvest, post-harvest, drying and pre-storage. Total aflatoxin occurrence on peanut kernels was analyzed by CD-ELISA (Competitive Direct-Enzyme Linked Immuno Sorbent Assays). Analysis results showed that aflatoxin contamination was not found on 96 samples sundried on drying sheet at experimental area whereas 41 of 42 samples sundried on field soil at the research areas were contaminated. Toxin levels in 42 contaminated samples were from 0.1 to 9.0 mu g kg(-1). Also, IAC-HPLC (Immunoaffinity Chromatography-Reversed-Phase High-Performance Liquid Chromatography) analysis was used for the 18 samples contiminated aflatoxin. The results from both the CD-ELISA and IAC-HPLC analysis were similar. Aflatoxin levels during drying and pre-storage were significantly higher than those during harvest and post-harvest. In conclusion, the drying and pre-storage terms are the most critical periods for aflatoxin contamination.