In this paper the specific interactions between poly(vinylpyridine) and copolymers of vinyl alcohol/vinyl acetate of different compositions have been studied by Fourier transform infrared spectroscopy (FTIR). Hydrogen bonding between both polymer components leads to significant spectral modification in hydroxyl, carbonyl, and pyridine rings spectral bands. Minor modifications in other spectral modes have also been detected. The spectral results indicate at least three competing equilibrium processes in the blends : copolymer slef-association (hydroxyl-hydroxyl and hydroxyl-carbonyl) and hydroxyl-pyridine interassociation. The Painter-Coleman association model for three interacting units was successfully applied. Finally, quantitative results show that hydroxyl-hydroxyl association is the predominant one.