The major causes of decline in fungal diversity are pollution, changes in atmospheric CO₂ concentrations, changes in the nitrogen cycle and acid rain, climate alterations, and the introduction of exotic species, all coincident to human population growth. For that, an understanding of the effect of pollution on fungal diversity in the environment is of paramount importance. The environmental problems in Bihar, India are growing rapidly which has a direct effect on the growth of fungal population. This include alteration to the fungal community structure in foods also. In the present investigation, during January 2008 to August 2008 fungal diversity was assessed on some common foods consumed in Bihar. For that, some common food items were considered viz; chicken,boiled potato, mixed vegetable, kheer, dal.The spoiled food samples were home made from some polluted areas and collected in sterilised plastic containers. The fungi isolated from these infected foods were identified and characterized with the help of authentic manuals of fungi. A mean of eight months data were calculated and placed in the table according to month wise frequency. Moisture content, oxidation- reduction potential, p^H , nutrient content, antimicrobial constituents, biological structures as well as relative humidity of environment and presence and concentration of gases in the  environment were the factors which regulated the microbial growth. The identified mycofloras were found as common in their occurrence in different types of foods under diverse environmental conditions, belonged mostly to the genus Aspergillus  and Penicillium viz; Aspergillus flavus, Aspergillus niger, Aspergillus japonicus and Penicillium citrinum ,Penicillium funiculosum. The genus of Aspergillus with 9 species followed by 6 species of Penicillium  occupied more than the total number of isolated fungal species.  Some members of Deuteromycetes and Zygomycetes were also isolated. The difference in the nature of organic materials expelled may be the cause of abundance of certain species in certain areas.