A compact high-T c superconducting (HTS) monolithic downconverter is presented. The HTS passive and active devices are integrated on one single chip to achieve compactness and high coupling efficiency. The downconverter consists of a HTS YBa 2Cu 3O 7-x (YBCO) bandpass filter for RF input, a lowpass filter for IF output, and a self-pumped step-edge Josephson heterodyne mixer fabricated on a 20 ×10mm MgO substrate. Characterisations of the HTS filters and the frequency response of the on-chip integrated downconverter are reported. The results demonstrate the potential of the HTS downconverter for applications in wireless communications.