Background and Objectives: Familial Mediterranean fever which is the prototype of the hereditary periodic fever syndromes is common in the countries around the Mediterranean Sea. Regarding the geographical position of the northwest of Iran, having Turkish originality and its vicinity to the Mediterranean Sea , the incidence of this disease is significant in Ardabil. The goal of this study was to introduce Familial Mediterranean Fever as a disease with significant outbreak in this area.

 Methods: This research is a descriptive study which has been done during one year from October 2004 to October 2005. According to the Tel-Hashomer criteria, the patients suffering from Familial Mediterranean Fever were collected from private clinics and pediatric rheumatology clinics records. Then from 112 patients only 74 ones were studied. All of the patients were interviewed and filled out a questionnaire.

 Results: Familial Mediterranean fever is common among children under 18 (76%) and more common in male than female. Abdominal pain has been the most common complaint (74%) and abdominal pain and fever (95% and 84% respectively) were the main clinical symptoms. The most common period of pain was 12-72 hours and the common recovery (attack free) period was from 1 week to 1 month (63/5%). Majority of the patients had hospital admission for diagnostic work up (85%) and some of them (32%) had been under surgical operation mistakenly. On the whole 92% of the patients had taken medications as a result of wrong diagnosis and 20% had positive familial history. 50% of the patients' parents were first degree relatives and in 59.5% delay in diagnosis was more than 3 years.

 Conclusion: Results of this study and introduction of this group of patients in a one-year research indicate that: Familial Mediterranean Fever is more common in the Northwest of Iran although physicians are not familiar with that. The common age for manifestation of this disease is under 18 and its presentation after the age of 40 is very rare.