Electron-beam initiated crosslinking of a poly(vinyl chloride)/epoxidized natural rubber blend (PVC/ENR), which contained trimethylolpropane triacrylate (TMPTA), was carried out over a range of irradiation doses (20-200 kGy) and concentrations of TMPTA (1-5 phr). The gelation dose was determined by a method proposed by Charlesby. It was evident from the gelation dose, resilience, hysteresis, glass-transition temperature (T-g), IR spectroscopy, and scanning electron microscopy studies that the miscible PVC/ENR blend underwent crosslinking by electron-beam irradiation. The acceleration of crosslinking by the TMPTA was further confirmed in this study. Agreement of the results with a theory relating the T-g with the distance between crosslinks provided further evidence of irradiation-induced crosslinking. The possible mechanism of crosslinking induced by the irradiation between PVC and ENR is also proposed.