Summary Ethrel promoted the rooting of hypocotyl cuttings of mung bean synergistically with IAA. TIBA inhibited rooting. The inhibition was enhanced by both IAA and ethrel used singly but was partially relieved when used in combination. Ethrel and IAA in combination also removed the inhibition caused by GAa more effectively than with either of them alone. Cuttings taken from young seedlings or seedlings grown in dark or defoliated did not respond synergistically to ethrel and IAA.