Walnut (Juglans regia) is highly nutritious and most favorite tree nut worldwide. China was at peak in global production of walnuts in 2012. Pakistan's walnut production was good in last years but its production reduced in recent years due to some post harvest losses. If these are not handled and stored properly, these may be susceptible to infestation, bacterial and fungal attack. In the context of enhancing the export quality by increasing the shelf-life of walnuts and meeting the quarantine standards, the appropriate dose of cobalt-60 gamma radiation according to our environmental conditions of storage was applied to see the effects on the susceptibility and liability of walnut kernels to infestation and microbial attack and it definitely worked.