Autoinflammatory diseases are defined as recurrent “unprovoked” inflammatory events which do not produce high-titer autoantibodies or antigen-specific T cells. There are currently eight hereditary forms of these diseases: Familial Mediterranean fever (FMF), hyperimmunoglobulinemia D with periodic fever syndrome (HIDS), tumor necrosis factor receptor-associated periodic syndrome (TRAPS), Muckle-Wells syndrome (MWS), familial cold autoinflammatory syndrome (FCAS), chronic infantile neurologic cutaneous articular (CINCA) syndrome or neonatal-onset multisystem inflammatory disease (NOMID), pyogenic sterile arthritis, pyoderma gangrenosum, acne (PAPA) and Blau syndrome. Apart from FMF (which has a prevalence of about 0.1 percent among non-Ashkenazi Jews, Armenians, Turks and Arabs), they are very rare disorders. FMF and HIDS are autosomal recessive diseases, all the other members of the family are autosomal and dominantly transmitted. Their common clinical features are recurrent and usually short attacks of synovitis and various skin eruptions; abdominal pain and fever are also frequently observed. The genes of all of these diseases have been discovered and, with the exception of HIDS, it was found that the proteins they encode share certain domains taking part in innate immunity and apoptosis. Thus it was evident that hereditary autoinflammatory diseases may help us understand better a number of important and prevalent pathologic events. We have reviewed the recent and rapidly accumulating knowledge on the molecular aspects of these disorders.