In this study, first principles calculation results of the all elastic parameters, characteristic Debye temperatures, Poisson's ratios, ultrasound velocities and full phonon dispersion spectra of two Ill-V group zincblende semiconductors, AlSb and GaSb, are presented. Calculations are based on plane wave basis sets together with Vanderbilt ultrasoft pseudopotentials in the framework of Density Functional Theory (DFT) with Perdew-Wang parameterization of generalized gradient approximation. The detailed total energy calculations are performed in order to obtain elastic stiffness coefficients using volume conserving (isochoric) strains on cubic zincblende phase. The phonon dispersion spectra are calculated in linear response approach. All calculated parameters as well as phonon dispersion spectra are in excellent agreement with experimental works and available theoretical calculations. (C) 2008 Elsevier B.V. All rights reserved.