The shielding constants, nuclear quadmpole coupling constants, and spin-spin coupling constants are computed for the ammonia-water complex. Four structures of the complex are considered. A series of multiconfiguration self-consistent field (MCSCF) wavefunctions is applied for the trans conformer to estimate the role of electron correlation, and a selected MCSCF function is next systematically used for all the other conformers. The largest changes of all the nuclear magnetic resonance (NMR) parameters with respect to the monomers are observed for the nuclei participating in the hydrogen bond, and they are similar for the trans and cis conformers. The parameter changes due to the interaction are significant also for both bifurcated structures of the complex, even though there is no hydrogen bond. The electron correlation effects are not negligible, in particular for the spin-spin coupling constants. © 2002 Wiley Periodicals, Inc. Int. J. Quantum Chem. 90.