Interpolymer complexes of methacrylic acid-acrylamide copolymer have been prepared by the interaction of its comonomer units with two different homopolymers, and also with a single homopolymer. The stability constants and related thermodynamic parameters (e.g., DELTAH-0 and DELTAS0) of the mixed complex were found to be significantly different from the SingLe homopolymer complexes. This has been attributed to neighboring group influence and destabilization of various interacting forces at different temperatures.