Human globin messenger RNA was isolated from reticulocytes of four Jewish patients of Kurdish origin with homozygous beta0-thalassemia. On translation in the wheat-germ cell-free system, messenger RNA from these patients directed extensive synthesis of alpha- and gamma-globin chains, but synthesis of beta-globin chains was not detectable. In contrast, nonthalassemic human globin messenger RNA directed the synthesis of essentially equimolar amounts of alpha- and beta-globin. The patterns of globin synthesized by beta0-thalassemic messenger RNA in the cell-free system were virtually identical to the patterns of globin synthesized in peripheral blood cells of these patients. beta0-thalassemic messenger RNA similarly failed to direct any detectable beta-globin synthesis in a micrococcal nuclease-treated rabbit reticulocyte lysate, even in the presence of an excess of purified eukaryotic initiation factor 2. These results strongly suggest that functional messenger RNA for beta-globin chains is absent in Kurdish Jews with homozygous beta0-thalassemia.