The electronic polarization of acetone in liquid water is obtained using an iterative procedure in the sequential Monte Carlo/quantum mechanics methodology. MP2/aug-cc-pVDZ calculations of the dipole moment of acetone in water are performed on statistically uncorrelated structures extracted from isothermic-isobaric MC simulations. After electrostatic equilibrium the calculated dipole moment of acetone is obtained as 4.80 +/- 0.03 D, with an increase of 60% compared to the gas phase value. This solute polarization is used to obtain the shift of 1650 +/- 42 cm(-1) for the n-pi* transition of acetone in water, in agreement with the experimental result of 1500-1700 cm(-1). (c) 2006 Published by Elsevier B.V.