  Polarized antiprotons can be produced in a storage ring by spin--dependent
interaction in a purely electron--polarized hydrogen gas target. The polarizing
process is based on spin transfer from the polarized electrons of the target
atoms to the orbiting antiprotons. After spin filtering for about two beam
lifetimes at energies $T\approx 40-170$ MeV using a dedicated large acceptance
ring, the antiproton beam polarization would reach $P=0.2-0.4$. Polarized
antiprotons would open new and unique research opportunities for spin--physics
experiments in $\bar{p}p$ interactions.
