In this study the effects of irradiation on colonies of fungi which develop on materials such as paper, parchment, etc. have been analyzed. The study analyzes both the irradiation of samples of damaged books and the irradiation of various pure species of fungi. Even with variations due to different experimental methods, irradiation is shown to be effective against such micro-organisms, even at relatively low doses (less than 1 Mrad). On the basis of these results, the possibility of irradiating books to disinfect them may therefore be considered.