Anatomical studies determined the effect of 0.8, 1.7, and 3.4 kg/ha of penoxalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine]; AC-92390 (N-sec-butyl-3-4-dimethyl-2,6-dinitrobenzenamine); oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide); and trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) on the cell structure of snap bean (Phaseolus vulgaris L. ‘Tenderette’) and soybean [Glycine max (L.) Merr. ‘Corsoy’]. Cellular abnormalities in the swollen and brittle area of the stem of treated plants included thinnerwalled cells, elongated xylem elements, hypertrophy and hyperplasia of cells, and anomalous rings of vascular tissue in the cortical region. Injury caused by the four herbicides was similar in snap bean and soybean.