Effects of group IIB metal oxides (viz., ZnO, CdO, and HgO) on ethylene thiourea (ETU) accelerated the curing of acrylic rubber (ACM) have been evaluated with a view to elucidate the cross-linking mechanism with special reference to the role of metal oxides. Best results are obtained with CdO in the presence of ETU. ZnO - CdO or CdO - HgO blends provide no synergism in the state and rate of cure. Formation of metal sulfide and chloride during the cross-linking reaction has been confirmed by XRD and XPS. Examination of FTIR spectra reveals that cross-linking occurs at the C - Cl cure site of the acrylic polymer. Based on spectral and chemical analysis, a reaction mechanism has been put forward.