Several common approaches are used for disinfection of water in this section, but using the approaches (e.g. chlorination) are accompanied with hazardous by-products and also lead to notable changes in odor and flavor of water. Gamma irradiation as an emerging method has been encouraged currently by FAO/WHO for water, wastewater and food treatment. Coliform bacteria belong to common contaminants of water and being used as an indicator of efficacy of water safety measures, including gamma irradiation. Current study was conducted to evaluate the efficacy of gamma irradiation to eradication of microbial contaminants from food industry water resources. Water samples were collected from food industries located around Tehran, capital of Iran. Samples from three major resources of food industry water system; Well, Tank and Recycled water were collected and one part of the samples irradiated with 137Cs gamma radiator. Treated and untreated samples were tested by standard Multiple-tubes fermentation technique for detection of coliform bacteria and MPN indexes were calculated. Gamma irradiation had killing effect on coliforms and leads to noticeable reduction in MPN indexes of treated water samples compared to untreated ones. With few modifications in radiation dose, it is expected to implant portable gamma radiators to treatment of water in food industry section.