Familial Mediterranean Fever (FMF) is a recessive inherited disorder affecting Sephardic Jews, Arabs, Armenians and Turks. The gene responsible for FMF was recently cloned and several disease-associated mutations have been described. We have evaluated seven MEFV mutations in 460 chromosomes of 230 unrelated patients with FMF living in Turkey, using PCR methods. The M694V allele accounted for 43.5% of the alleles studied and 19.1% of the patients were homozygous. The M680I, V726A and M694I mutations were responsible for 12.0%, 11.1% and 2.8% of the patients respectively. R761H, K695R and E148Q were rarely encountered. Two thirds of the disease alleles were attributed to three common mutations: M694V , M680V and V726A, but only 54% of the patients carried one or two of the three mutations. Adding the four rarer mutations increased these figures to 72% and 60%, respectively. Altogether, 79.6% of the patients bore at least one of the main mutations, and 84.3% carried at least one of the seven mutations studied. The 28 patients suffering also from amyloidosis carried at least one of five mutations, M694V being the most common. These results suggest that the origin of FMF in Turkey is heterogenous, all common mutations are associated with amyloidosis. Further, rapid and accurate molecular diagnosis of FMF is feasible in most cases.