The moleeular-hydrodynamic description of Langmuir-Blodgett deposition presented in this study relates the velocity of deposition to the activation free energy of adsorption occurring along the three-phase contact line, the density of the hydrophilic headgroups (considered as adsorption centers), and the viscosity, density, and surface tension of the liquid phase. It introduces rigorously defined dynamic contact angles that can be easily determined in the experiment. It is shown that the pure molecular-kinetic and hydrodynamic theories do not adequately describe the experimental relationship between velocity of deposition and dynamic contact angles while the molecular-hydrodynamic one fits the experimental data up to the maximal velocity, U-max, at which a liquid film is entrained during the upstroke stage of deposition. Comparison between this theory and experiment points out that the hydrodynamic deformation of the fluid interface is negligible when deposition is performed from dilute aqueous subsolutions but can become important for viscous subsolutions and deposition at high surface pressure. Analysis of energy dissipation in the three-phase zone and in the bulk of the moving meniscus shows that the nonhydrodynamic dissipation in the three-phase contact zone prevails in the whole velocity range up to U-max. This dissipation depends on the nature of the hydrophilic headgroups, and their modification via counterion adsorption significantly changes its value. It is shown that substitution of the carboxylic groups by barium-carboxylate ones decreases this dissipation and causes an increase of U-max probably due to facilitated dehydration of the heads.