The interactions of acetone molecules with clusters of Au-3 and Au-5 are investigated by using a density functional theory (DFT) within a generalized gradient approximation (GGA). The geometries, adsorption energies and deformation electron density distributions are used to analyse these interactions. The present calculations show that more than one acetone molecules can be adsorbed onto small gold clusters, and this adsorption is different from that of single molecule absorption. The coordination number of the adsorption site on the gold cluster is the dominant factor responsible for the strength of the interactions. The effects of the Au-O bond lengths in the complexes on adsorption energies between Au clusters and acetone molecules are also examined.