The elastic properties of two series of lanthanum aluminosilicate glasses (15La(2)O(3)-xAl(2)O(3)-(85 - X)SiO2 and 25La(2)O(3)-yAl(2)O(3)-(75 - y)SiO2, where x, y = 15, 20, 25, 30, 35 mol%), were obtained by the ultrasonic pulse-echo technique, at room temperature. The correlation of elastic stiffness, the cross-link density, and the fractal bond connectivity of these glasses are discussed. The derived experimental values of Young's modulus, bulk modulus, shear modulus and Poisson's ratio for our glasses are compared with those theoretically calculated values in terms of the Makishima-Mackenzie model. (C) 2003 Elsevier Ltd. All rights reserved.