Familial Mediterranean fever (FMF) is a recurrent inflammatory disorder characterized by short episodes of fever, peritonitis, pleuritis, and arthritis. While FMF has been shown to be inherited in an autosomal recessive fashion in both non-Ashkenazi Jews and Armenian families, clinical differences have raised the possibility of genetic heterogeneity. As its pathogenesis is unknown, mapping of the gene for FMF may provide the first objective method for early and accurate diagnosis of this disease. After excluding 45% of the entire human genome, we studied 14 Armenian and 9 non-Ashkenazi Jewish families with FMF and tested linkage with the alpha-globin locus on chromosome 16. Analysis of the PvuII length polymorphism of the 3' HVR (hypervariable region) probe showed significant linkage with the FMF gene (maximum lod score [lodmax] = 9.76 at maximum recombination fraction [theta] = .076). In the Armenians, the lodmax = 3.61 at theta = .10; and for the non-Ashkenazi Jews, lodmax = 6.28 at theta = .06. There was no evidence for genetic heterogeneity between the Armenians and the non-Ashkenazi Jews (chi 2 = 1.28; P = .26) or within either ethnic group (chi 2 = .00; P = .50). Thus, the gene for FMF is linked to the alpha-globin complex on chromosome 16p in both non-Ashkenazi Jews and Armenians.