Intramolecular screening in hydrogen-bonded polymer blends has its genesis in chain connectivity. The covalent linkages that occur between polymer segments results in an accentuation of the number of same-chain contacts compared to that calculated on the basis of a simple random mixing of segments. Using experimental infrared spectroscopic data derived from blends of random copolymers ofn-butyl methacrylate-stat-4-vinylphenol with styrene-stat-2-vinyl pyridine, strong evidence for the presence of intramolecular screening has been obtained. This is a significant factor that must be taken into consideration in theories of the mixing of polymers.