Periodic fever syndromes comprise a group of disorders characterized by attacks of seemingly unprovoked inflammation. The genetic causes of five hereditary autoinflammatory syndromes have been identified in the last few years: familial Mediterranean fever, the cryopyrinopathies [Muckle-Wells, chronic infantile neurological, cutaneous, articular syndrome (CINCA) and familial autoinflammatory syndromes], TNF-receptor associated periodic syndrome, cyclic neutropenia syndrome and periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome. The study of periodic fever syndromes has progressed from clinical characterization to genetic analysis and to the definition of the functional defects linking genes or domains to apoptotic proteins and signal transduction pathways. This new research opens the way for more specific treatment options with a further improvement in prognosis and outcome.