Cheese-whey utilization has been the subject of much research. BOD reductions of higher than 75%, with the concomitant production of biogas, ethanol, single cell protein or another marketable product, have been achieved and about half the whey produced nowadays is not a pollutant but a resource. However annual world cheese-whey production is increasing and new bioproductions are being sought through biotechnology in order to get full use of the whey produced. In this paper the most representative applications of cheese whey being exploited and under research are briefly discussed. Copyright (C) 1996 Published by Elsevier Science Ltd.