Onychomycosis is the most common nail disease and describes the invasion of the nail by fungi. Different clinical patterns of infection depend on the way and the extent by which fungi colonise the nail: distal subungual onychomycosis, proximal subungual onychomycosis, white superficial onychomycosis, endonyx onychomycosis and total dystropic onychomycosis. The type of nail invasion depends on both the fungus responsible and on host susceptibility. Treatment of onychomycosis depends on the clinical type of the onychomycosis, the number of affected nails and the severity of nail involvement. The goals for antifungal therapy are mycological cure and a normal looking nail. In this paper the treatment of onychomycosis with oral antifungal agents will be reviewed.