Recently, various methods for preparing a flexible electrode for implementing a wearable sensor have beenintroduced. Wearable sensors show similar tendency to use various polymer substrates, which provides elasticity suitable tothe motion of human body. In this paper, a highly elastic silver nanowire based electrode was prepared on a sponge-basedstretchable substrate, and electrical properties were evaluated. Silver nanowires were grown using a wet chemical synthesis,impregnated into a plasma-treated sponge, and then heat treated at a low temperature. In particular, the plasma surface treatmentof the sponge enables uniform coating of silver nanowires. The flexible sponge electrode showed reliable electrical resistancechanges over 160 repeated tensile-compression cycles.