A respiratory monitor comprises: a first sensor (20, 70) configured to generate a respiration-related motion monitoring signal (72) indicative of respiration related motion; a second sensor (20, 22, 80, 82) configured to generate a sound monitoring signal (84) indicative of respiration-related sound; and a signals synthesizer (90) configured to synthesize a respiratory monitor signal (46) based on the respiration-related motion monitoring signal and the respiration-related sound monitoring signal. A sensor for use in respiratory monitoring comprises an accelerometer (30) and a magnetometer (32) together defining a unitary sensor (20) configured for attachment to a respiring subject (10) so as to move as a unit responsive to respiration related motion of the respiring subject.