The extraction rates of amino acids from alkaline aqueous solution into an emulsion liquid membrane containing tri-n-octylmethylammonium chloride as a carrier and Paranox 100 as an emulsifier were measured using a stirred transfer cell. The effects of agitation speed (0.33-0.66 rev s(-1)), amino acid concentrations (0.5-50 mol m(-3)) and temperature (10-45 degrees C) on the extraction rates were examined. The results were analyzed by a double-him model. The mass transfer coefficients of amino acids (0.26-1.58 x 10(-5) m s(-1)) and their complexes (0.60-1.72 x 10(-5) m s(-1)) were found to correlate well with the hydrophobicities of the amino acids. It was found that the surfactant layer influenced the mass transfer processes of both amino acids in the aqueous film and their complexes in the organic him. The permeation of amino acids with a large hydrophobicity through the emulsion liquid membrane was promoted by both high distribution and larger mass transfer rates.