By a slight modification of the procedure described by Gratecos et al. (Gratecos, D., Knibiehler, M., Benoit, V. and Sémériva, M. (1978) Biochim. Biophpys. Acta 512, 508-524), the basolateral and brush border membranes of rabbit enterocytes have been purified concomitantly from the same aliquot of mucosa. The two types of membrane have been obtained with the same yield (15%) and enrichment of specific markers (18-fold). The presence in the basolateral membrane of hydrolases known to be specific of the brush border membrane has been confirmed by using immunological techniques.