Ag─Cd alloys have been internally oxidized to produce CdO precipitates within the Ag matrix. Electron microscopy studies revealed that the Ag/CdO interfaces are incoherent which can be explained by the presumably weak bonding forces across the interface and the large lattice misfit. A comparison of lattice images recorded experimentally with those simulated by computer, based on different interfacial structure models, shows that an oxygen plane forms the terminating layer on the oxide side, even at interfacial steps. This result is supported by thermodynamic considerations.