Water absorption and other properties of polyamides can potentially be modified by blending with polyesters. The compatibility of a polyester ionomer melt-blended with nylon-6 is studied in this article, examining the effect of blending upon crystallization behaviors, morphology, thermal/mechanical properties, and water absorption. Comparisons of the crystallization behaviors of the ionomer/nylon-6 blends with poly(ethylene terephthalate)/nylon-6 blends suggest increased compatibility due to greater interactions between the two phases. The results indicate that the presence of a significant amount of the ionomeric groups is required to improve polyester compatibility with polyamides. (c) 2006 Wiley Periodicals, Inc.