The present study was carried out to evaluate the effects of microwave (MW) radiation on viability of wood decaying fungi. The white rot (Trametes versicolor) and brown rot (Rhodonia placenta) fungi were grown on bamboo culm-samples. The mycelium growths were observed in controlled as well as microwave treated samples. The results showed that the viability of fungi decreased according to the applied MW time. This study proved the ability of the microwaves and exposure time MW3 (180 seconds) to kill the fungal colonies and do not allow for the growth of fungal spores, means the rate of growth of fungal colonies is inversely proportional to time of microwave exposure.