This work describes the interaction of nylon6 (N6) with the random copolymer poly(vinyl butyral) (PVB) at various hydroxyl levels of residual vinyl alcohol in the PVB. The methylene and amide groups of N6 were observed to interact favorably with the PVB, resulting in thermodynamic miscibility at PVB compositions in the range of 0.50-0.65 volume fractions of vinyl alcohol in PVB. The polymers' interaction parameters were estimated to be -0.04 and 0.04 for chi(N6/VA) and chi(N6/PVB). respectively. Miscibility parameter results compared favorably with the miscibility window determined.