The phase equilibria of alpha-phenylglycine in sodium hydroxide solutions at pH = 11 and 12 with the extractant trialkylmethylammonium chloride (Tomac) dissolved in kerosene and toluene and with Amberlite XAD-4 resin coated with Tomac at 30degreesC is reported. The extraction of alpha-phenylglycine and co-extraction of hydroxyl ions take place simultaneously by ion exchange reactions with the extractant. Phase equilibria are discussed as a function of a-phenylglycine concentration, pH of the aqueous phase and Tomac concentration either in the organic phase or in resin phase. An equilibrium model, which considers the hydroxyl ion co-extraction, has been used for the correlation of the equilibrium data.