The kinetics of liquid membrane extraction of organic solutes (phenol, pyridine,m-toluidine, phenylalanine) from aqueous solution is studied. The experiments were carried out in a Lewis-type cell and in a liquid membrane device with flowing aqueous films and a circulating organic membrane liquid. From the results it can be concluded that when the goal is to obtain a more concentrated stripping solution, higher flow rates of the feed should be used; when a more complete recovery or separation of different organic solutes is aimed at, lower flow rates should be used.