Objective: To investigate the effect of anti-interleukin-1 (anti-IL-1) treatment on the frequency and severity of attacks and other disease-related clinical parameters and to evaluate the adverse effects associated with anti-IL-1 treatment in 26 patients with refractory familial mediterranean fever (FMF).Methods: The study included 26 FMF patients followed up in our centre using colchicine for 4 months to 30 years. The treatment was switched to anti-IL-1 treatment for various reasons; 20 cases were resistant to colchicine, 8 were intolerant to colchicine, and 3 had prolonged arthritis under colchicine. Clinical response was monitored through the number of attacks, and laboratory inflammation was monitored through erythrocyte sedimentation rate, C-reactive protein, and serum amyloid A concentrations. Colchicine resistance was defined as at least two attacks/month together with C-reactive protein and serum amyloid A levels above the normal range between attacks. The colchicine dose was increased to 2mg/day before they were considered colchicine-resistant.Results: 24 patients used anakinra (100mg/day), and 2 used canakinumab (150mg/month), for -36 months. Sixteen patients with colchicine resistance had no attacks under anti-IL-1 treatment, and 4 had decreased frequency and duration of attacks. Seven of 8 patients intolerant to colchicine used anakinra, and 6 were attack-free under treatment, while 1 using canakinumab had attacks under treatment. One patient with prolonged arthritis used canakinumab but arthritis showed progression and the treatment was changed to IL-6 inhibitor. Three patients had injection site erythema and one had fatigue with anti-IL-1 treatment. Topical steroids with systemic antihistaminics were sufficient for symptom control in two cases, but canakinumab treatment was given due to severe injection site erythema in one case.Conclusion: Anti-IL-1 agents are rational treatment modalities in patients resistant or intolerant to colchicine. Anti-IL-1 agents can control FMF attacks quite effectively and they have a promising role in the treatment of FMF.