Whey proteins have practical significance on grounds of their nutritive and functional values. However, the presence of fat negatively affects their flavour and foaming properties. The objective of the research was to determine the effect of fat content on foaming properties of whey protein concentrates. Whey protein concentrates, those with fat and those with fat reduced by chitosan, were compared as regards their foaming properties; all of them had a declared protein content of 35 % (WPC 35) and of 80 % (WPC 80). Furthermore, the foaming properties of whey proteins were compared with those of albumin in egg white (EWP). Upon the application of chitosan, the whey protein solutions, i.e. WPC 35 chitosan and WPC 80 chitosan, showed a higher foaming yield level (respectively: 721.7 % and 776.7 %) than that of WPC 35 and WPC 80 (respectively: 338.3 % and 588.3 %) and of EWP and EWP-W (respectively: 555.0 % and 536.7 %). The solutions of WPC 35 chitosan and WPC 80 chitosan showed higher values of foam overrun (750.8 % and 636.8 %, respectively) than the solutions of WPC 35 and WPC 80 (520.93 %, 568.0 %) and than the natural albumin in egg white (EWP) and the albumin of high foaming activity in egg white (EWPW) (572.6 % and 595.7 %, respectively). The stability of foams produced from WPC 35 chitosan and WPC 80 chitosan solutions was higher (93.6 % and 98.1 %, respectively) compared to the foam stability produced from WPC 35 solution (32.5 %) and from WPC 80 solution (87.1 %); it was comparable  with the foam stability from EWP (97.6 %) and EWP-W (100.0 %). The application of chitosan contributed to a significant decrease in turbidity of WPC.