Atypical clinical forms of familial Mediterranean fever (FMF) can be misdiagnosed as therapy-resistant epigastric pain syndrome (EPS) for they share many of the same clinical features, such as abdominal pain. Thus, we aimed to determined the frequency of FMF in patients who were followed with a diagnosis of therapy-resistant EPS. Seventy-five patients with therapy-resistant EPS and 20 controls were involved in the study. To detect the FMF in patients with therapy-resistant EPS, Tel-Hashomer criteria, family history of FMF were researched and recorded. We performed performed MEFV gene analysis on all patients. Forty-three patients with EPS (57.3%) had MEFV gene mutations and the carrier rate was 30.0%. The most common MEFV gene alteration was R202Q (55.8%), followed by E148Q (16.2%), R761H (16.2%), V726A (9.3%), M680I (9.3%) and M694V (4.6%). Rarely seen mutations in the Turkish population were also identified: K695R (2.3%), L110P (2.3%) and G304R (2.3%). Eight patients with EPS were diagnosed with FMF and started on colchicine therapy. Three patients with compound heterozygosities for three mutations, two patients with compound het-erozygosities for two mutations (K695R/V726A and R202Q/R761H), one patient with homozygous R202Q, one patient with heterozygous R202Q mutation and one patient with nonR202Q heterozygous mutation (G304R/-) had clinical FMF symptoms and were started on colchicine therapy. Patients who have therapy-resistant EPS should also be questioned about FMF, especially in high risk populations.