A method for removing free fatty acids from fats or oils of biological origin or their steam distillates by extracting the free fatty acids with a mixture of basic organic nitrogen compounds and water as an extraction medium at a temperature below the boiling point of the organic nitrogen compounds. The content of the basic organic nitrogen compounds in the extraction medium is 20-30% by weight. In this manner, the formation of a viscous soapstock which is difficult to remove is prevented. The boiling point of the basic organic nitrogen compounds used is the same as or above boiling point of water and below the boiling point of the fatty acids to be extracted in order to enable simple recovery of the extraction medium.