In this research, time dependency of low fat- low cholesterol mayonnaise with 35 and 50% oil at the different concentration of Lepidium perfoliatum seed gum (0.5, 0.75 and 1%) and whey protein concentrate were studied. Data were fitted with famous rheological models. Results showed that all samples had thixotropic behavior and their viscosity decreased with time. The rate and extent of viscosity decay were dependent on the applied shear rate, percent of fat and gum concentration. The viscosity of the samples tended to decay more rapidly at higher shear rates toward an equilibrium viscosity. Samples containing less fat, showed lower viscosity and approached rapidly to the equilibrium. Addition of gum to mayonnaise caused higher viscosity and samples become like the full-fat sample. In this study, the breakdown rate constant did not show a clear trend with increasing gum concentration and shear rate.