We calculate the pion's valence-quark momentum-fraction probability distrib
ution using a Dyson-Schwinger equation model. Valence quarks with an active
mass of 0.30 GeV carry 71% of the pions momentum at a resolving scale q(0)
= 0.54 GeV = 1/(0.37 fm). The shape of the calculated distribution is char
acteristic of a strongly bound system and, evolved from q(0) to q = 2 GeV,
it yields first, second, and third moments in agreement with lattice and ph
enomenological estimates. and valence-quarks carrying 49% of the pion's mom
entum. However, pointwise there is a discrepancy between our calculated dis
tribution and that hitherto inferred from parametrizations of extant pion-n
ucleon Drell-Yan data.