The influence of pH on foaming of whey protein isolates (WPI) and concentrates (WPC 80 and WPC 65) dispersions was investigated due to the lack of studies on the whipping process on the protein aggregation in prefoam solutions, resulting foams and drainage serum. The WPI foams were superior compared to WPC ones. pH values of 5.0 and 9.0 were optimal for the foaming of all preparations, while pH 3.0 caused a deterioration of their foamability. For the WPI foams, a correlation was found between the yield stress and phase angle. pH 9.0 promoted the protein aggregation, especially in the prefoam WPI solutions.