Onychomycoses constitute pathologies frequently seen in dermatological practice worldwide. Usually, they are caused by two groups of pathogenic fungi: dermatophytes and yeasts of the Candida genus. However, in a small fraction of the cases, the etiologic agents comprise nondermatophyte molds, belonging to several genera and species. The objective of this study was to present two cases of onychomycosis associated to the mold Scytalidium dimidiatum in patients residing in two cities of Santa Catarina State, Brazil. Aspects of fungal pathogenesis, as well as the epidemiological characteristics and laboratory diagnosis, are discussed.