Objective: Molds produce poisons called mycotoxins,OTA is one of the most relevant mycotoxins which is generally produced by Aspergillus, its presence in food and feed products being regulated in many countries. Methods: From the first May to the last October2011,sampling was done according to"CBS" instructions for indoor and outdoor situations. Isolates were identified and recorded in the laboratory on fungal biomass prepared a sample group and crude cell extracts were prepared in the laboratory and Ochratoxin was produced by fungal isolates in cell extracts was measured by using ELISA. Results: Significance rate is higher than 0.05.Thus the changes in Ochratoxin production don’t depend on various levels of geographic area ,it can be stated that in the Aspergillus species studied in this geographic area,it is expected to observe Ochratoxin production in 2.5-5ppb range. Discussion: According to the fact that maximum limit toxin in food stocks is 5 ppb,it must be greatly noticed into consideration.While it must be taken greatly into attention that some of isolated studied in the area produced the toxin in great amounts (20-25ppb).That may be dangerous for health significance of correlation between the toxin rate and the original province where sampling of studied isolates was performed is 100% for Guilan and Mazandaran and 99% for Golestan provinces.It may be stated that it is not possible to find as specific area with considered field conditions to be the growth area or origin of a given Aspergillus species with a given density of their presence or their dependence to a area or dependence of their classification the section of subgenus groups in the standard rules for classification of Aspergilli.