The considerable polarization of hyperons produced at high xF has been known for a long time and has been interpreted with various theoretical models in terms of the constituents' spin. Recently, the analyzing power in inclusive Λ0 hyperon production has also been measured using the 200 GeV/c Fermilab polarized proton beam. The covered kinematic range is 0.2≤xF≤1.0 and 0.1≤pT≤1.5 GeV/c. The data indicate a negative asymmetry at large xF and moderate pT. These results can further test the current ideas on the underlying mechanisms for hyperon polarization.