Novel compatibilized polyoxymethylene/thermoplastic polyurethane (POM/TPU) blends are successfully developed using multifunctional chain extender, Joncryl ADR-4368, as the compatibilizer. The outstanding compatibilization efficiency of Joncryl on POM/TPU blend was demonstrated by its even higher mechanical properties with only 0.5 wt % of Joncryl than those with 5 wt % of three commonly used compatibilizers. Addition of only 0.5 wt % Joncryl can double the impact strength and significantly improve its tensile strength and flexural strength for POM/TPU (75/25) blend. SEM images show that Joncryl can reduce TPU particle size and enhance the interfacial interactions between POM and TPU. The interparticle distance of TPU in POM/TPU/Joncryl blends was calculated as 0.2 mu m, quite close to the critical matrix ligament thickness of POM/TPU blends (0.18 mu m). The impact force profile vividly shows that the addition of Joncyl in POM/TPU blends can dramatically increase the total impact energy absorbed by this blend system and enhance the interfacial interactions between POM and TPU. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 127: 3033-3039, 2013