Objective: Familial Mediterranean fever (FMF) is an autosomal recessive autoimmune disease, presenting with the attacks of fever and inflammation of serous membranes. One of the leading causes of death in autoimmune rheumatologic diseases is cardiovascular events. The purpose of this study is to evaluate the effects of FMF on the autonomic nerve and cardiovascular systems by measuring the indices of heart rate variability (HRV).Material and Methods: Thirty FMF patients and the same number of healthy volunteers were enrolled to the study. Standard deviation of all R-R intervals (SDNN), the square root of the sum of the square of the differences between successive R-R intervals (RMSSD), standard deviation of 5-minute mean values of R-R interval (SDANN), low frequency (LF), and high frequency (HF) were measured.Results: Time domain indices (SDNN, SDANN, and RMSSD) were: 124.67±40.79, 129.87±36.43 (p=0.605); 11.43±38.41, 11.23±38.98 (p=0.984); and 33.43±17.39, 38.17±12.8 (p=0.235) for FMF patients and controls, respectively, and similar in both groups. Frequency domain indices (HF, LF, and LF/HF) were: 290.41±290.25, 322.20±222.54 (p=0.639); 596.16±334.07, 805.80±471.00 (p=0.051); and 3.57±2.57, 3.05±1.40 (p=0.338) for FMF patients and controls, respectively, and similar in both groups.Conclusion: The HRV parameters were similar in both groups. However, studies including larger populations and using different methods are required to clarify if autonomic dysfunction exists in patients with FMF