We have investigated the ability of PBEO, M05-class, and M06-class of density functional theory (OFT) to describe the geometries, vibrational frequencies, binding energies and electronic properties of aluminum clusters, Al-n(x) (n = 2-9, x = 0, +/- 1). The DFT results are compared to those obtained from CCSD(T)/CBS calculations and experimental data when available. For Al-n clusters (n <= 7) the average error difference CUED) for the electron affinities and ionization potential compared to the experimental data are only 0.14 and 0.15 eV at PBEO/aug-cc-pVTZ level and 0.11 and 0.13, respectively for the CBST-Q calculations. (C) 2013 Elsevier B.V. All rights reserved.