According to the increased fungi contaminations and related damages, microbiologist's incentive in considering the fungal contaminations in human habitats had increased. Some of fungi cause disease through production of toxins in animals and thus in humans. Since these toxins are not easily distinguishable, then it is crucial to study their characteristics. Aspergillus are among the most important toxigenic fungi which are found abundantly in northern Iran habitats where is one of most important habitats of Iran and which is the main source for many feed and food stuffs in the state thus we aimed to study on DON production characteristics in culture medium by 24 Aspergillus spp. isolated from different geographic areas of northern Iran isolates collection.