The present state of the use of separation techniques in the identification and characterization of allergens and in the monitoring of the quality of allergenic preparations is critically surveyed. After a brief summary of the range of problems encountered in obtaining and in the application of allergenic preparations and of the principal physico-chemical properties of allergens, chromatographic and electromigration methods of separation of components of these systems and their combinations with immunochemical procedures are discussed, with selected examples of application to real materials. Emphasis is placed on evaluation of the most important analytical parameters, such as reliability of the results, separation efficiency and resolution, and on the most recent results in the field.