Aim: To determine the thiol/disulfide homeostasis in patients with familial Mediterranean fever (FMF) and its correlation with the levels of inflammatory markers consisting of white blood cell count, erythrocyte sedimentation rate, C-reactive protein and fibrinogen. Material and Method: This study was performed in the internal Medicine department of Mustafa Kemal University Hospital in Turkey. A total of 27 FMF patients in the attack period (AP), 33 FMF patients in the attack-free period (AFP), and 36 healthy controls participated in this study. Thiol/disulfide profile parameters were detected using the novel method of Erel and Neselioglu. Results: Total and native thiol levels of the FMF-AP group were markedly lower than those of healthy controls, while the difference in disulfide level was not statistically significant. Thiol/disulfide levels in the FMF-AFP group were similar to the levels in both the FMF-AP group and healthy controls. Correlation analysis showed a negative correlation between fibrinogen levels and total and native thiol levels, while there was a positive correlation between white blood cell count and disulfide levels in the FMF-AP group. Discussion: The findings suggest that decreased concentrations of total and native thiol in patients with FMF-AP are likely to be an outcome of inflammation-induced oxidative stress.