This review outlines recent data on treatment modalities and outcomes with antifungal therapy in onychomycosis. Included are topical, mechanical, chemical and systemic treatments or a combination thereof. Topical treatments, or transungual drug delivery systems (TUDDS), including ciclopirox and amorolfine were shown to be effective if used alone for mild-moderate nail involvement. Specifically, superficial white onychomycosis (SWO) restricted to the dorsum of the nail plate and moderate distal lateral subungual onychomycosis (DLSO). Mechanical treatments were mostly effective as adjuncts to topical therapy which include nail avulsion and abrasion. In particular, partial nail avulsion aids topical therapy in DLSO and partial subungual onychomycosis for a more effective therapy. Chemical avulsion is a painless method of debridement which uses a keratinolysis formula that is effective only in limited and early disease. Systemic therapies have been shown to be effective with terbinafine and itraconazole is suggested as being the most cost-effective therapy. Systemic therapies require consideration of side effects and monitoring by both patient and physician prior to treatment application. An effective suggestion is the use of a topical with debridement for mild-moderate onychomycosis and systemic (terbinafine) plus topical for severe onychomycosis. Most treatment modalities will require long-term use from 3 to 9 months to be most effective, with strategies presented in Part II of this review.