The Republican Temple (1st century BC) contains a series of frescoes in unfavorable environmental conditions. The experiments showed a very high relative humidity (100% from April to October, between 60% and 90% in Winter). These environmental conditions are extremely favorable to the development of molds, which were abundant on the frescoes' surface. Eight species of fungi were obtained: <i>Aspergillus restrictus, A. versicolor, Penicillum spinolosum, P. velatinum, Mammaria echinobotryoides, Acremonium rosoleum, Stachybotris atra</i> and <i>Blassomyces sp.</i> In vitro the growth of these fungi was completely inhibited by the addition of the fungicide Metain 101 to the culture medium.