All the positively charged proteins in whey were bound simultaneously to a cation exchange column, rinsed free of contaminants and then eluted selectively to produce different fractions. Three different elution procedures were used: (1) a single elution buffer to make whey protein isolate (WPI); (2) two elution buffers to make alpha-lactalbumin (ALA) and WPI depleted in ALA; and (3) four elution buffers to make ALA, WPI depleted in ALA, lactoperoxidase, and lactoferrin. The process uses an adsorbent and buffers that are inexpensive and food-grade, operates at a high flow rate, and minimizes the use of salt for elution. The process developed in this work is a significant improvement over commercial practice for the fractionation of proteins from whey. (C) 2003 Elsevier Ltd. All rights reserved.