This research demonstrates that dead fungal biomass from Aspergillus flavus can effectively remove radioactive cesium and strontium from contaminated water, offering an affordable and environmentally friendly alternative to traditional treatment methods. The fungus shows excellent ability to capture strontium ions (90% removal) and can be reused multiple times by treating it with nitric acid. This finding is particularly relevant following nuclear accidents like Fukushima and provides a sustainable solution for treating radioactive wastewater from nuclear facilities.