IN 1957 Smithies1, using the technique of starch-gel electrophoresis, described inherited variants of human β-globulins. Smithies and Hiller2 established the identity of these β-globulins with the iron-binding protein, trans-ferrin, and this was afterwards confirmed with iron-59 and autoradiography3. During the past few years widespread sampling of human populations has demonstrated the existence so far of 14 transferrins. In order of decreasing mobility in starch-gel electrophoresis these are4: B0, BO–1 B1, B1–2, B2, B3, C, D0, D4 (D0–1), Dmontreal Dchi, D1, D2, D3. The present communication reports another transferrin of the B series.