Background: Blood neutrophil to lymphocyte ratio(NLR) and mean platelet volume(MPV) both have been used as a simple marker of inflammation in many disorders. Here, we aimed to investigate the relationship between NLR, MPV, and familial Mediterranean fever(FMF). Materials and Methods: In this retrospective study, the files of FMF patients in pediatric rheumatology outpatient clinic were reviewed. There were 160 participants(68.4%) in the FMF patient group and 74 participants(31.6%) in the control group. Ninety of patients were in attack-free period, and 70 were in attack period. Results: The highest values of NLR were found in the patients at attack period. Patients in attack-free period and the participants in control group had similar levels of NLR(1.71 +/- 0.83 and 1.91 +/- 1.86 respectively) (P=0.457), and they had lower ratios than the patients did at attack period(4.10 +/- 3.11) (P< 0.001for both). There was no significant difference between MPV values of attack patients(8.35 +/- 4.91) and attack-free patients(8.43 +/- 1.15) (P= 0.074). MPV values of attack patients and attack-free patients were significantly higher than control group(7.99 +/- 0.81) (P< 0.001 for both). Conclusion: NLR ratio may indicate FMF attack period. Since there was no significant difference between attack-free patients and control groups, NLR ratio cannot be used as a subclinical inflammation marker. However, NLR could be a useful predictor of inflammation in FMF patients. On the other hand, since our attack and attack-free patients have similar MPV values and both had greater MPV values than control group, we suggest that MPV may be used to show subclinical inflammation.