Familial Mediterranean fever, also known as a periodic disease or recurrent polyserositis, is an autosomal-recessive disorder characterized by recurrent attacks of fever, synovitis, peritonitis, or pleuritis. In patients presenting with typical clinical features and with an appropriate ethnic origin, the diagnosis can be made without genetic confirmation. The discovery of the MEFV gene has led to a molecular approach to diagnosis, aiming at improving the global diagnosis of the disease. Some diseases, mainly vasculitides, seem to be more common in familial Mediterranean fever. The “decreased antiinflammatory response” hypothesis and other putative mechanisms (cytokines) in familial Mediterranean fever can also take a predisposing and facilitating role in type 1 diabetes autoimmune pathogenicity. We describe a previously unreported association between familial Mediterranean fever and type 1 diabetes in a 9-year-old girl.