Diphytanolphosphatidylcholine (DPhPC) is a lipid widely used in the study of membrane channel activity. Herein we report the results of a constant temperature (T=25 degrees C) and constant pressure (p = 1 atm) molecular-dynamics (MD) simulation of a hydrated liquid crystal phase DPhPC bilayer. The simulated system consisted of a periodically replicated cell containing 64 lipid and 1792 water molecules. The system was monitored during a trajectory spanning more than one nanosecond. The resulting unconstrained area density per lipid a,agreed quantitatively with experimental data. The calculated bilayer profile and acyl chain order parameters also compared favorably with x-ray scattering and nuclear magnetic resonance (NMR) data.