Onychomycosis is a fungal infection of the nail plate or nail bed. It does not usually cure itself and it can trigger more infectious lesions in other parts of the body. The reported prevalence of onychomycosis is increasing in Western countries, presumably due to lifestyle changes and the ageing of the population. Approximately 10% of the general population, 20% of the population aged >60 years, up to 50% of people aged >70 years and up to one-third of diabetic individuals have onychomycosis. Care should be taken for the accurate diagnosis and timely treatment of toenail onychomycosis to prevent complications. Current treatment options have relatively limited therapeutic success, particularly long-term. Oral medications are associated with high recurrence rates and treatment failure, and are not suitable for many cases due to potential adverse effects. Topical medications are recommended only for mild to moderate cases. The cost of therapies may also be prohibitive in some cases. In the light of these issues, more research is warranted for the investigation and development of more effective and economical options for the treatment and prophylaxis of toenail onychomycosis. In patient populations such as diabetic individuals, where onychomycosis can provoke lower extremity complications, professional podiatry care of toenails and feet should be encouraged.