A liver α-[ 3H]-tocopherol binding protein was partially purified using ammonium sulfate fractionation, gel filtration and ion-exchange chromatography from the 100,000 × g liver supernatant of rats fed a low vitamin E diet for 3 months and administered 200 μCi of α-[ 3H]-tocopherol. The labelled protein was used to study the transfer and binding of α-tocopherol to liver microsomes. In vitro incubations showed that the transfer of α-tocopherol was directly proportional to the amount of α-[ 3H]-tocopherol binding protein and to the amount of microsomal protein present. Moreover, the transfer of α-tocopherol increased with the temperature of incubation. A 3.8 fold excess of unlabelled α-tocopherol (bound to the same protein) inhibited the transfer of labelled α-tocopherol by 62%. These data suggest that an α-tocopherol binding protein could play a role in the intracellular transfer of α-tocopherol.