The faculty for and degree of oligo(C)-poly(G) interaction is described as an essentially chain length - sensitive phenomenon. At neutral pH under suitable experimental conditions, oligocytidylates of chain length greater than four associate with poly(G) to form double-stranded structures, as does poly(C). The extent of complex formation increases with degree of polymerization. The complex at acid pH is shown to be triple-stranded, of stoicheometry 2C/1G. The observation of a 2G/1C artifact is discussed.