Fructans are biopolymers used as food additives to modify physical properties such as texture and viscosity, while providing health benefits. They are extracted from chicory roots and roots of other plants such as agavaceas. Fructans of the genus Agave have structural differences with respect to chicory inulin, in terms of their interaction with other components. The effect of concentration and temperature on the rheological properties of fructan solutions obtained from agave and inulin was studied. The intrinsic viscosity, critical concentration and capacity of gel formation were determined in conjunction with the effects of temperature on these properties. The samples exhibited similar values of intrinsic viscosity (0.060–0.072 dL g−1), showing a critical concentration (C *) between 170 and 180 g L−1. However, only inulin formed a viscoelastic solid (gel) at concentrations higher than C*. The apparent viscosity of the solutions of both agave fructans and the inulin decreased in relation to an increase in temperature. In the concentration range of 20–100 g L−1, both biopolymers showed no variation in viscosity. It is suggested that agave fructans can be used as food additives like those from chicory inulin in the concentration range of 20–100 g L−1.