The static and dynamic yield stresses have been obtained for two different silica-fumed aqueous suspensions (2.5% and 7.5% v/v). An experimental method proposed by Cheng [D.C-H. Cheng, Rheol. Acta, 25, (1986), 542-554] for thixotropic systems has been used to obtain the dynamic yield stress. To get the static yield stress a shear stress ramp has been applied. Analysis of the results let us conclude that we can compare the structural level reached for different thixotropic suspensions that have undergone the same shear load.