The change of compatibility of poly(ethylene-co-vinyl alcohol) (EVOH)/LDPE blends induced by gamma-ray radiation was studied. Gel extraction experiment results show that the gel fraction of blends increases linearly with the content of LDPE and reaches a maximum at 100 kGy, because neat EVOH is difficult to cross-link by irradiation. A comparison of theoretical and experimental gel contents indicates that some EVOH molecular chains enter the LDPE gel network. The peak at 3363 cm(-1) on the Fourier transform infrared spectrum of pure blend gel is assigned to typical stretching of an -OH bond, which indicates that a "graft" reaction occurs in the interface between EVOH and LDPE phases during the irradiation process. Mechanical property measurement results support such a structural change. The tensile strength of cross-linked blends increases with absorbed dose first, reaches a maximum value at 150 kGy, and then decreases with dose. A similar trend can also be observed in bending tests. (C) 2009 Wiley Periodicals, Inc. Adv Polym Techn 28: 192-198, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20160