Familial Mediterranean fever (FMF) is a disease characterized by recurrent, self-limiting fever and serositis and caused by altered pyrin due to mutated MEFV gene. The aim of this study was to investigate clinical manifestations and MEFV mutations among patients with FMF and healthy controls in the Aegean region of Turkey. This study included 308 patients and 164 healthy controls. Patients were divided into three groups according to Tel-Hashomer criteria; definitive, probable, and suspicious. Among the patients, 146 were women (47.4%) and 162 were men (52.6%). The mean age (+/- SD) of the patients at the diagnosis was 9.6 +/- A 3.95 (range 0.5-18). The mean age (+/- SD) at onset of the symptom was 6.2 +/- A 3.95 (range 1-18). Symptoms were seen earlier onset in definitive group than the suspicious group in our cohort (4.7 +/- A 3.9 years, 6.6 +/- A 3.9 years, respectively; P = 0.001). Clinical features were abdominal pain (83.1%), fever (55%), arthritis (17.1%), myalgia (4.5%), pleuritis (10%), and erysipelas-like erythema (7.7%). Fever, arthralgia, arthritis, chest pain, and amyloidosis were found statistically significant more in definitive group than suspicious group (P < 0.001, P < 0.001, P < 0.001, P < 0.05, and P < 0.001, respectively). MEFV gene mutations were identified in 199 patients (64.6%). The most commonly encountered MEFV mutation among the patients was M694V homozygote (25%). M694V homozygous mutation was found most frequently in definitive FMF group than other groups (49, 9, 8.9%, respectively). To our knowledge that FMF should be suspected in the case of non-specific but recurrent attacks of serositis and high fever, and molecular analysis should be performed in order to make diagnosis of FMF.