MUCH attention has been focused recently on the design and construction of nanoscale structures by supramolecular assembly(1-5). One of the most promising approaches to constructing nanoscale structures is the use of specific interactions between polymers and receptors, as exemplified by biological systems. Recently, polyrotaxanes-complexes in which several cyclic molecules are threaded on the main chains(6-11) or side chains(12) of polymers-have been synthesized with crown ethers or cyclodextrins as the cyclic components. Here we report the self-assembly of double-stranded inclusion complexes of poly(ethylene glycol) with gamma-cyclodextrin, in which two polymer chains are threaded through the macrocycles. These complexes might be useful precursors to more complex supramolecular assemblies such as polycatenanes.