The strong hydrogen bonds have been examined by using OPLS and AMBER force fields, and a new water model (WLP) has been suggested. Results on geometries and hydrogen-bond energies have been compared with the corresponding experimental data and quantum mechanical calculations. The OPLS method was found to give a more reliable description of strong hydrogen bonds than AMBER. A new set of OPLS parameters are reported for ten amino acid moieties. Improvement over the OPLS and AMBER force fields is apparent.