A careful examination of the liquid drainage in packed-bed reactors using liquid superficial velocities characteristic of trickle how regime and no gas velocity is both experimentally and theoretically carried out. True free-Bowing or dynamic liquid holdups are determined in two different reactors packed with porous and nonporous particles employing several liquids. Dynamic liquid holdups are shown to be higher than those determined directly from total liquid drained volumes, which are usually reported when the drainage method is applied. It is found that a model of laminar liquid films properly addresses the influence of liquid superficial velocities and of liquid viscosity on the dynamic liquid holdup within the experimental conditions studied. A simple quantitative phenomenological model to describe the drainage kinetics is developed and is independently verified from experimental data. Satisfactory agreement is found for all the examined conditions.