Onychomycosis accounts for one third of fungal skin infections. Because only about one half of nail dystrophies are caused by fungus, the diagnosis should be confirmed by potassium hydroxide preparation, culture or histology before treatment is started. Newer, more effective antifungal agents have made treating onychomycosis easier. Terbinafine and itraconazole are the therapeutic agents of choice. Although the U.S. Food and Drug Administration has not labeled fluconazole for the treatment of onychomycosis, early efficacy data are promising. Continuous oral terbinafine therapy is most effective against dermatophytes, which are responsible for the majority of onychomycosis cases. Intermittent pulse dosing with itraconazole is as safe and effective as short-term continuous therapy but more economical and convenient. With careful monitoring, patients treated with the newer antifungal agents have a good chance of achieving relief from onychomycosis and its complications.