Onychodystrophies are various pathological processes in the nail apparatus of infectious and non-infectious nature, related to changes in its morphology. The most common cause of nail changes is a fungal infection. However, onychodystrophy can be a manifestation of dermatological diseases, trauma, medication, systemic and tumor processes. Since the clinical symptoms of onychodystrophies are unspecific, sometimes it can cause difficulties in making a diagnosis. This photo gallery presents clinical pictures of diseases that a physician may encounter in everyday practice.