In this paper we want to demonstrate whether higher than normal levels of RDW, and lower than normal levels of MPV can be used as indicators of subclinical inflammation and tools for treatment decision in FMF or not. The participants in this study included 89 patients with FMF during attack-free periods and 30 healthy controls. The RDW and platelet counts were significantly higher, while the MPV was significantly lower in the patients with FMF group than healthy control group (P<0.001; P=0.005; P<0.001, resp.). In the attack-free FMF group, a negative correlation was found between the MPV and RDW values (P<0.001, r=-0.40). The positive correlation was found between the RDW and ESR (r=0.23, P=0.028). And the negative correlation was found between the MPV and CRP (r=-0.216, P=0.042). Consequently, our results suggest that low MPV and high RDW levels may provide additional information about subclinical inflammation in FMF patients. But other strong predisposing factors affecting subclinical inflammation in FMF should be considered. Further studies with large numbers of patients are needed. Treatment of FMF should include not only prevention of acute attacks but also decreasing of the subclinical inflammation.