Combined communications-transponder avionics radio units are provided. In one embodiment, a communications-transponder avionics radio unit is provided. The unit comprises: a first component bay having a communications (COMM) radio unit; a second component bay having a transponder unit; a control display unit divided into a first control display interface area for a COMM radio control display in communication with the COMM radio unit, and a second control display interface area for a transponder radio control display in communication with the Transponder Unit; and an enclosure housing the first component bay, the second component bay and the control display unit.