A method and parametrization scheme which allow fast and accurate calculations of hydration free energies are described. The solute is treated as a polarizable cavity of a shape defined by the molecular surface, containing point charges at the location of atomic nuclei. Electrostatic contributions to solvation are derived from:finite difference solutions of the Poisson equation (FDPB method). Nonpolar (cavity/van der Waals) energies are added as a surface area dependent term, with a single surface tension coefficient (gamma) derived from hydrocarbon solubility in water. Atomic charges and radii are obtained by modifying existing force-field or quantum-mechanically-derived values, by fitting to experimental solvation energies of small organic molecules. A new, simple parameter set (parameters for solvation energy, PARSE) is developed specifically for the FDPB/gamma method, by choosing atomic charges and radii which reproduce the estimated contributions to solvation of simple functional groups. The PARSE parameters reproduce hydration free energies for a test set of 67 molecules with an average error of 0.4 kcal/mol. For amino acid side chain and peptide backbone analogs the average error is only 0.1 kcal/mol.