The aim of this work was to apply conventional extraction methods and extraction with supercritical fluid, using ethanol or supercritical CO2 (scCO(2)) as a pure solvent and scCO(2) with ethanol as a co-solvent, to obtain polyphenols from cocoa seeds. After the extraction, the polyphenols were retained by polymeric membranes. In the concentration process, commercial nanofiltration polymeric membranes, models DL and HL (GE-Osmonics), and NF and NF-90 (Filmtec-Dow), were used, and for the reverse osmosis models SG (GE-Osmonics) and BW-30 (Filmtec-Dow) were used. The results indicated that the amount of polyphenols extracted varied from 8% to 40% according to the amount of solvent and co-solvent added, for the pressure and ethanol degree used. The membranes used showed polyphenol rejections of between 80% and 95%, and good results for permeate flux, mechanical resistance to the transmembrane pressure applied, and the behavior regarding the chemical action exerted by the compounds of the extract, were obtained. (C) 2007 Elsevier B.V. All rights reserved.