Background: In this study we investigated the potential of neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), mean platelet volume (MPV), and red cell width distribution (RDW) as new inflammatory markers to identify chronic inflammations during symptom-free periods in children diagnosed with Familial Mediterranean Fever (FMF).Material/Methods: The study included 153 children diagnosed with FMF based on the Tel-Hashomer Criteria, and 90 healthy volunteers. Hospital records were obtained to collect NLR, PLR, MPV, RDW, and FMF scores and the FMF mutation analyses of the patients enrolled in the study. Data on proteinuria were also collected and defined as a protein/ creatinine ratio >0.2.Results: NLR, PLR, MPV, and RDW were significantly higher in symptom-free FMF patients than in the control group. C-reactive protein values also weakly correlated with NLR, PLR, MPV, and RDW, but the correlation was not statistically significant. NLR had the strongest correlation with CRP. The NLR cut-off point to indicate subclinical inflammation in symptom-free FMF patients was calculated to be 1.65.Conclusions: NLR, PLR, MPV, and RDW are potential subclinical inflammation markers in patients with FMF. NLR, PLR, MPV, and RDW values are higher in patients with FMF during symptom-free periods. NLR was found to be the most reliable marker for subclinical inflammation when compared to PLR, MPV, and RDW. We also found that these markers are not significantly higher in proteinuric patients when compared with levels in non-proteinuric patients.