Abstract The electrochemiluminescence of the tris- (2,2′-bipyridine) ruthenium (II) dication in aqueous oxalate and in acetonitrile is substantially enhanced by simultaneous irradiation with 40–60 kHz ultrasound. Edge effects and electrode patchiness are diminished, quantum efficiency is increased and lower cell voltages are required. Reproducibility and stability are improved and electrode fouling is minimized. Electrochemiluminescence (ECL) and sono-electrochemiluminescence (SECL) seem to be of similar origin but a weak sonoluminescence (SL), also observed, is of a different origin. Preliminary experiments upon the luminol and 1-aminopyrene electrochemiluminescence systems suggest that different mechanisms for ultrasonic influence may operate in each case.