The elastic properties of a series of low-silica calcium alumino-silicate (LSCAS) glasses are investigated by room temperature ultrasonic pulse-echo technique. Both longitudinal and transverse velocities of these glasses are composition dependent. The experimental results are used to obtain elastic moduli. The correlation of elastic stiffness, the cross-link density, and the fractal bond connectivity of the glass are discussed. The values of elastic moduli (including Young's modulus, bulk modulus, shear modulus and Poisson's ratio), derived from experimental data for our glasses are compared with those theoretically calculated in terms of Makishima-Mackenzie model and a model by Rocherulle et al. (C) 2002 Elsevier Science B.V All rights reserved.