Background: Coagulation abnormalities have been reported in familial Mediterranean fever (FMF) patients with amyloidosis and nephrotic syndrome; but there is not enough data about the continuity of the thrombogenic activity in FMF patients in clinical remission. The purpose of this study was to assess thrombin activatable fibrinolysis inhibitor (TAFI) levels and its relationship with fibrinolytic activity and also evaluate relationships between mutations and clinical signs in attack-free patients without amyloidosis. Methods: Seventy-nine FMF patients and 40 healthy adults were included. The study group was divided into five groups as follows: first group, homozygote M694V; second group, homozygote M680I; third group, M694V in one allele, the other allele have other mutations or not; fourth group, other mutations; and fifth group, no mutation. Results: Serum TAFI levels were significantly increased in patients compared with healthy individuals (116.64 +/- 21.8 vs. 78.48 +/- 19.7 mu g/mL, p<0.001) and a positive correlation was detected between TAFI antigen level and erythrocyte sedimentation rate and C-reactive protein levels (r = 0.247, p = 0.029 and r = 0.252, p = 0.032, respectively). Mean fibrinogen and TAFI levels were significantly higher in Group 1 than the other groups (p = 0.04 and p = 0.001, respectively) and in Group 3 it was higher than Groups 2, 4 and 5 (p = 0.04 and p = 0.001, respectively). Conclusions: High level of TAFI antigen in attack-free period of FMF disease shows ongoing subclinical inflammation and hypercoagulability. Clinicians should be careful about thrombosis even in patients at clinical remission. Also, genetic tests must be considered to predict clinical outcome and to reduce complications of FMF disease.