Results of theoretical investigation on size-dependent structural, electronic and optical properties of stoichiometric GanAsn clusters are presented. The calculations are performed by using a simplified linear combination of atomic orbital-density-functional theory-local density approximation-tight-binding(LCAO-DFT-LDA-TB) method and consider clusters with n up to around 100. We considered finite spherical parts of the zinc-blende crystals which are allowed to relax to the closest local-energy-minimum structure. The results include the radial distribution of atoms and of Mulliken populations, the electronic energy levels (in particular HOMO and LUMO), the band gap and the stability as a function of size and composition. (c) 2005 Elsevier B.V. All rights reserved.