Introduction: Familial Mediterranean fever (FMF, MIM# 249100) is an autosomal genetic disease. FMF shows a marked ethnic distribution being most frequently observed in Turkish, Armenian, Jewish and Arabic communities. Since the cloning of the MEFV gene, about 280 mutations have been associated with FMF. M694V, V726A, E148Q, M694I, and M680I are the five most frequently encountered mutations. Differences in clinical presentation of FMF among different ethnic groups have been studied. However, phenotype–genotype correlations in FMF have not been decisively resolved. The aim of this work is to correlate the clinical phenotypes of FMF patients to their gene mutation. Patients and methods: The study was done on 55 patients with FMF who are diagnosed primary clinically using Turkish pediatric criteria. Genetic identification of their gene mutation was performed and only Patient with definite identified mutation in MEFV. Results: This study was done on 55 patients 27 male (49.1%) and 28 female (50.9%) with mean age ± SD is 8.28 years ± 4.27. The mean age of diagnosis was 5.47 y ± 2.66 years and the diagnosis lag was 5.36 ± 2.55 y. Fever was the most prevalent manifestation in our patient as 96.3% of them experienced fever and the second most frequent symptom was abdominal pain 90.9% followed by Chest pain represented 81.8% of patients. Family history was positive in 61.8% Fifteen patients had amyloidosis at diagnosis (27.3%) while forty patients did not have elevated amyloid at diagnosis (72.7%). Fifty one patient showed good response to colchicine (92.7%) while only four did not show response (7.3%). The severity of attacks were mild in 29 patients (52.7%) and moderate in 6 patients (10.9%) and sever in 20 patients (36.4%) M694V was the most prevalent mutation followed by M694I, V726A, M680I, R761H and K695R respectively. In our study, compound heterozygous mutations were the commonest (44%) followed by honozygos mutation(33%) and lastly heterozygous mutations (23%). Conclusion: in Egypt no significant difference between homozygous and heterozygous FMF patients regarding their clinical presentations but type of mutation affects the severity of clinical presentation