Familial Mediterranean fever is characterized by recurrent polyserositis episodes associated with fever. However, the clinical spectrum of this disease has been expanded recently and myalgia is now a frequently recognized component. Protracted febrile myalgia syndrome was first described in patients with familial Mediterranean fever in 1994. This syndrome is characterized by severe paralyzing myalgia, high fever, abdominal pain, diarrhea, arthritis/arthralgia, and transient vasculitic rashes mimicking Henoch-Schonlein purpura. Recently, we evaluated 6 patients with the clinical picture of protracted febrile myalgia syndrome in our clinic. One of them was a patient with known familial Mediterranean fever, but the others were subsequently diagnosed to have familial Mediterranean fever by mutational analyses. Thus, introduction of genetic analysis would possibly change the diagnostic criteria for familial Mediterranean fever. In addition, all 6 patients presented in the spring months when streptococcal infections are at their peak rate and 3 of them had elevated ASO levels indicating that streptococci could be one of the agents triggering protracted febrile myalgia syndrome.