The aim of the study was to determine the economical impact of juvenile idiopathic arthritis (JIA) and familial Mediterranean fever (FMF) in Turkey. A total of 100 patients (69 F/31 M) with JIA and 100 with FMF (68 F/32 F) who were consecutively seen in the outpatient clinic of the pediatric rheumatology department at Cerrahpasa Medical School between August 2008 and January 2009 were studied. Cost data were collected through a questionnaire filled out by the parents. The mean age (JIA: 11 +/- A 5 years; FMF:12 +/- A 4 years) and mean disease duration (JIA:5 +/- A 3 years; FMF: 4 +/- A 3 years) of the patients were similar. JIA patients were assigned to 5 subtypes (polyarticular: n = 45, oligoarticular: n = 30, systemic onset: n = 13, psoriatic: n = 6, and enthesopathy-related JIA: n = 6). Forty-nine percent of the patients with JIA were treated with anti-TNF drugs and 61% with DMARDs. All patients with FMF were using colchicine. The total annual cost of JIA (a,not sign3,994 +/- A 4,101) was considerably higher than that of FMF (a,not sign162 +/- A 77) (P < 0.001). Medication fee was the major determinant of total costs in both diseases constituting 85% in JIA and 39% in FMF. Among the subtypes of JIA, total annual costs were the highest among patients with polyarticular type (a,not sign6,045 +/- A 4,078). Medications especially anti-TNF drugs were the major contributor among all determinants of costs in JIA. The low costs of health care system and prominent changes in the health care policies for the last 5 years in Turkey might have played role in our findings.