Four kinds of fungi were cultured on various media, including different surfactants, and their growth was compared. Cladosporium cladosporioides and Aureobasidium sp., which are common fungi in indoor environments, were inhibited by detergents, especially synthetic detergent. On the other hand, Scolecobasidium sp. and Exophiala alcalophila, the dominant varieties inside washing machines, were not inhibited. Moreover, growth of the latter two fungi was promoted even on media containing 0.25% of detergent. Scolecobasidium sp. and E. alcalophila are thought to utilize detergent as a nutrient, and to be adapted to the environmental conditions inside washing machines.