Multiplexers have been fabricated using high-temperature superconductors (I-ITS). Superconducting YBa2Cu3O7-x films were deposited on MgO, a substrate by using pulsed laser deposition (PLD). A conventional photolithographic method was used to produce the superconducting multiplexer pattern. Epitaxial YBCO films with c.-axis orientation were grown on MgO (100) substrates. Superconducting transition temperatures were measured at 89 K. Simulated results: of the superconducting multiplexer consisting of hairpin type filters show an insertion loss of 1.2 dB. The measured frequency response of superconducting multiplexer was compared with the simulation results.