In this paper the interactions of poly(monoethyl itaconate) with poly(2-vinylpyridine) and poly(4-vinylpyridine) have been studied. Polymer blends or polycomplexes can be obtained, depending on the solvent employed. The stoichiometry found for the polycomplexes obtained was 2:1 of monoethyl itaconate:pyridine repeat units. Polymer complexes do not show a standard glass transition temperature. On the contrary, blends involving poly(monoethyl itaconate) and poly(2-vinylpyridine) show a broad glass transition. The thermal degradation behaviours of complexes and blends do not differ substantially from those of the pure components. Fourier-transform infra-red spectroscopy was used to study the hydrogen-bonding interactions in complexes and blends.