The author deals in the submitted paper with the problem of onychomycoses not only from the cosmetic but in particular from the medical aspect. Onychomycoses account for as many as 50 % of all problems affecting nails and about 10 % of skin diseases. Very frequently onychomycosis is associated with tinea pedis. The author deals in detail, based on data in the literature, with the aetiology and views regarding the pathogenesis of the disease. She mentions various external, internal and predisposing factors which are involved in the increasing number of onychomycoses in recent years. She describes the clinical picture of all four basic forms of the disease and analyzes differential diagnostic aspects. She describes in more detail other factors participating in the development of onychomycoses such as the host and site specificity, geographical conditions, age, sex, genetic factors and others. The author also draws attention to diagnostic laboratory difficulties, in particular identification by cultivation. In the conclusion she mentions contemporary possibilities of local and general treatment where in recent years substantial advances were made.

        Key words: onychomycosis, prevalence, diagnosis, therapy.