Stretch-activated chloride currents (I Cl,SA ) have been considered to be a component of volume-activated chloride currents (I Cl,vol ) for some time. This is due to a similarity in biophysical and pharmacological properties that involve a membrane curvature-induced mechanism and rearrangement of the cytoskeleton induced by cell swelling or membrane stretch. In the present study, we demonstrated that current density, along with the time taken from the activation of currents to the peak, were significantly different between the two currents, in highly metastatic human hepatocellular carcinoma cells. In addition, the activation of I Cl,vol or I Cl,SA , induced maximally by hypotonic solutions or membrane stretch, respectively, did not affect the following activation of the other one. Moreover, neither inhibition of I Cl,vol by sh-ClC-3 transfection, nor functional blocking of I Cl,vol by intracellular dialysis of anti-ClC-3 antibody had an effect on the activation and properties of I Cl,SA . Collectively, our results suggest that I Cl,SA is different from I Cl,vol in activation mechanism and/or in molecular entity responsible for formation of the currents. ClC-3 is involved in the activation of I Cl,vol , but not of I Cl,SA .