Onychomycosis caused by nondermatophyte molds are rare. Here we are reporting 2 cases of onychomycosis in apparently immunocompetent individuals, caused by Penicillium marneffei –the fungus which is generally considered either as a contaminant or an opportunistic pathogen capable of producing disease only in immunocompromised individuals. Previous therapy with Griseofulvin, assuming that the infection might be due to one of the members of dermatophytes, was proved to be unsuccessful and after initiation of Ketoconazole therapy gradual recovery occurred both clinically and microbiologically.