The prevalence of onychomycosis has been estimated at approximately 6.48% (95% confidence interval 6.09–6.88%) within the Canadian population. Dermatophytes are the most commonly cultured organisms, appearing in approximately 75 to 91% of nails with fungal involvement, with Trichophyton rubrum and Tricophyton mentagrophytes most commonly isolated. However, Candida spp and nondermatophyte molds are also sometimes cultured. The most common presentation is distal and lateral subungual onychomycosis (DLSO), which can involve 75% of patients with pedal onychomycosis. The distribution of DLSO, superficial white onychomycosis, and proximal subungual onychomycosis (PSO) has been reported to be 360:59:1 in patients with mycologic confirmation of onychomycosis; however, some reported that the incidence of PSO is slightly higher in immunocompromised individuals. Age, gender, family history, and the presence of tinea pedis are all elements associated with a nail fungal infection. In addition, many conditions, including diabetes mellitus, immune disorders, and vascular disease, have been associated with the presence of onychomycosis. When choosing the best treatment regimen for individuals with onychomycosis, it is very important to consider all of the factors involved, including the infecting species, the presentation of the disease, the level of disease progression, and its predisposing factors.