Sunn-hemp (Crotalaria juncea L.) was tested as a green manure for beans (Phaseolus vulgaris L.) in several localities of the State of São Paulo. The green manure was planted in the same area that was subsequently sown with beans. Incorporation of the whole plants or only their leaves were compared. The mean yield increase resulting from the treatments when compared with the checks was 41 % in the first case and 28 % in the second.