Ab initio molecular orbital calculations at the G3(GCP) level were conducted for the alkali cation-alcohol complexes (M+-L, where M+ = Li+, Na+, and K+; L = methanol, ethylene glycol, propan-1,2-diol, propan-1,3-diol and propan-1,2,3-triol). In general, these cations maximize the number of M+ . . . O interactions with the ligands. The role of intramolecular hydrogen bonding, ligand polarizability, ligand deformations, number of M+ 0 interactions and the M. 0 distances in governing M+-L affinities was discussed. The computationally less expensive G2(MP2,SVP)-FC/ ASC models were found to yield affinities in good agreement against the G3(GCP) benchmark, but the agreement deteriorates somewhat with increasing number of M+ . . . O interactions. (C) 2002 Elsevier Science B.V. All rights reserved.