Extracts in ethanol and ethanol-ammonia of dried leaves from Catharanthus roseus, gathered at Rio de Janeiro state, were adsorbed in a strongly acidic cation exchange resin with sulfonic acid group, using the finite bath method, resulting in an alkaloid retained fraction and an acidic and neutral unretained fraction. High Performance Liquid Chromatography showed the isolation of the alkaloid fraction to be highly selective and with good performance, with an absence of alkaloids in the unretained fraction, while the retained fraction presented 1,54-6,35 mg/g of vindoline and 0,12-0,91 mg/g of vinblastine, common for an alkaloid-rich concentrate, usually obtained by classic extraction with several steps using solvents.