Multiple genotyping studies have been carried out in order to clarify the epidemiology of fungal infections, more specifically to determine the sources, transmission routes, and colonization patterns of fungal isolates. In this review, the results obtained in genotyping investigations of Aspergillus isolates are summarized and discussed. Furthermore, we examine the epidemiologic studies of Candida albicans, Exophiala dermatitidis and Scedosporium apiospermum infections in patients with cystic fibrosis. Relative to Aspergillus fumigatus, colonization of the respiratory tract by multiple strains, and of deep organs by only a single strain were observed. On the other hand, the few studies which focused on other fungi isolated from patients with cystic fibrosis have suggested that colonization occurs primarily by a dominant genotype.