The United States Smithsonian Institution’s National Air and Space Museum preserves the world’s largest collection of spacesuits and their components relating to the American space program. Included in this collection are historically significant suits from the Apollo lunar missions which took place between 1968 and 1972. The Apollo suits are composed of multiple layers, many which have begun to degrade. The role of microorganisms in the deterioration of the space suits was investigated in this study. Fungi belonging to the genera Paecilmyces and Cladosporium were cultured from two synthetic polymers contained within the suits. Fungal growth occurred rapidly, and isolates were capable of degrading the synthetic polymers. Scanning electron microscopy was used to observe development of fungal hyphae on individual fibers of the cloth. Our data indicate that the growth of these fungi on the suit materials was a contributing factor to the deterioration of the interior layers of the Apollo spacesuits.