Leakage of electrolytes from leaf discs of treated bean (Phaseolus velgaris L.) plant was the criterion used to investigate the effect of four herbicides on the permeability of leaf-cell membrane. CGA 82725 (2-propynyl 2-((3, 5-dichloro-2 pyridinyl) oxy) phenoxy prpanate) at increased significantly cell membrane permeability within 1 h after 12 h treatment. Significant increase in cell membrane permeability was also detected at of DOWCO 453 (Haloxy-methyl 2-(4 (3-chloro- 5-(trifuluoromethyl)-2-pyridinyl) phenoxy) propanate. The effect of dinoseb (2-(1-methylpropyl)-4, 6-dintrophenol) on cell premeability was detected at after 12h. The highest conductivity measurement was obtained from paraquat (1, 1'- dimethyl-4, 4'-bipyridinium ion). Increase in cell membrane permeability was not always associated with injury symptoms such as appearance of necrotic area in leaves.