Abstract: Background and Objective: Mycotoxins are secondary metabolites of fungi producing toxin, those compounds were appeared in feed and food are unavoidable. Ochratoxin A (OTA) was first described as a toxic compound produced by Aspergillus ochraceus, latterly there are numerous strains of molds identified as ochratoxin excreted such as Penicillium verrucosum and Penicillium nordicum. Cereal is important component of the daily diet in Egypt. This study was undertaken to determine the presence of OTA in wheat from Egyptian fields and markets. During seven seasons (2009-2014) there is variation in the environmental condition. Materials and Methods: Wheat samples of ten governorates were tested for ochratoxin A contamination all over the seasons. Samples were tested for its contamination by toxigenic fungi against the changes in meteorological data, the results were analyzed statistically by M stat program version 6. Results: The average temperature ranges and the relative humidity had been changed and it was swing low and high, which had been resulted in difference between fungi types and amount of mycotoxins excretion. Ochratoxin A concentration in positive samples of wheat ranged between 2.1-24.9 μg kg–1 for first season and 1.3-21.4 μg kg–1 for last season. Wherever, the temperature changed up by mean of 2-5°C and humidity increased up. Conclusion: Mycotoxins are climate sub-ordinated plant and storage linked problems, also affected by non-designed factors (bioavailability of micro-nutrients, pests and insects damage) that are successively driven by climatic situation changes. Along with of those causes, climate performs as the key agro-ecosystem command force of fungal colonization and mycotoxins excrete.