The miscibility of poly(styrene-co-4-vinylphenyldimethylsilanol) (ST-VPDMS) and poly(n-butyl methacrylate) (PBMA) blends has been investigated by means of DSC and FT-IR spectroscopy. It was found that miscible blends were formed only for the copolymers containing 9-34 mol % 4-vinylphenyldimethylsilanol (VPDMS). The glass transition behavior of the miscible blends was analyzed by recently proposed equations in terms of the physical meaning of the fitting parameters. The results of FT-IR study were found to be fully consistent with the observation of the miscibility window obtained from glass transition temperature measurements. Quantitative information concerning intermolecular hydrogen bond interaction in the carbonyl stretching vibration region of the miscible blends was obtained by curve-fitting method.