Reported are two cases of suspected onychomycosis with participation of Cryptendoxyla hypophloia. The species C. hypophloia have not been isolated from human and animal clinical material yet. It is a rarely reported cleistothecial ascomycete that has been found to be naturally present on cellulose-rich materials. Its strains tested in a laboratory demonstrated very good susceptibility to terbinafine. The identification of isolates was verified based on rDNA sequencing and by comparison with C. hypophloia ex-type strain.