Fouling caused by sweet cheese whey and reconstituted whey powder solutions was studied in a Centritherm evaporator, with the behavior being estimated by measuring the change in the overall heat transfer coefficients with the time. It was found that there was no fouling detectable for the reconstituted whey powder solution. For sweet cheese whey, the fouling rate was strongly linked with the evaporating temperature and temperature difference. Visual observation showed that the deposit layer on the evaporator surface was very thin and soft, and like the type A milk deposit described by other investigators. A high velocity of liquid film delayed the formation of deposit on the surface. Some interactions between the evaporation temperature, feed flow rate, rotating speed, and temperature difference are discussed. The fouling is caused by denaturation of bovine serum albumin following a second-order rate reaction.