Nanosized ceria was fabricated in the channels of a porous coordination polymer (PCP) by the sol-gel polycondensation of cerium tetraisopropoxide. The resulting composite was characterized by IR, UV-vis, XRD, and XPS measurements, and the obtained ceria was found to be composed of a higher concentration of Ce3+ as compared to that of bulk synthesized ceria. Gas sorption of the composite showed the presence of ceria nanoparticles inside the channels of the PCP, which gave oxygen affinity for the PCP.