Abstract: A solution containing a metal alkoxide or oligomers thereof, a vinyl carboxylate polymer and an organic solvent is used, and, while low boiling substances containing the organic solvent is removed, both polycondensation of the metal alkoxide or oligomers thereof and saponification of the vinyl carboxylate polymer are conducted in parallel with each other and in the same reaction zone. On the occasion, the metal alkoxide or oligomers thereof is used in an amount of the metal atom present in the metal alkoxide or oligomers thereof of 0.01 to 100 moles based on 100 moles of the acyl group originating from the vinyl carboxylate unit present in the vinyl carboxylate polymer. This process can produce vinyl alcohol polymer compositions comprising a metal oxide without causing property unevenness, the compositions being capable of maintaining their excellent gas-barrier properties when exposed to high-temperature and high-humidity conditions or after being repeatedly bent.