['Dermatophytes are the main cause of onychomycoses, but various non-dermatophyte filamentous fungi are often isolated from abnormal nails.', 'Our aim was the in situ identification of the fungal infectious agent in 8 cases of onychomycoses which could not be cured after systemic terbinafine and itraconazole treatment.', 'Fungal DNA was extracted from nail samples, and infectious fungi were identified by restriction fragment length polymorphism (RFLP) of amplified fungal ribosomal DNA using a previously described PCR/RFLP assay.', 'PCR/RFLP identification of fungi in nails allows the identification of the infectious agent: Fusarium sp., Acremonium sp. and Aspergillus sp. were found as a sole infectious agent in 5, 2 and 1 cases, respectively.'] Does onychomycosis insensitive to systemic terbinafine and azole treatments reveal non-dermatophyte moulds as infectious agents?