Prion diseases are a family of progressive neurodegenerative disorders caused by prions. There are four human prion diseases: Creutzfeldt-Jakob disease, Gerstmann-Straussler-Scheinker syndrome, fatal insomnia and Kuru. They can arise in three different ways: acquired, familial or sporadic. We review clinical presentations, pathophysiology, morphological picture, diagnostic procedures and available treatment options of prion diseases.