An experimental miscibility map for 2,3-dimethylbutadiene-stat-4-vinylphenol (DMBVPh) blends with ethylene-stat-vinyl acetate (EVA) is obtained and compared to theoretical calculations. The number of hydrogen-bonded carbonyl groups in these systems is measured by FTIR spectroscopy and some systematic trends are apparent. It is shown that the miscibility of DMBVPh/EVA blends is much more sensitive to the difference in solubility parameters than to the degree of hydrogen bonding. However, the contribution from hydrogen bonding in these mixtures is important and is significantly influenced by screening effects. A simple correlation for the dependence of the screening effect on the average spacing of functional groups in a chain is proposed and tested.