The self-consistent anisotropic field theory for chain molecules in inhomogeneous systems has been applied to the analysis of ionic behavior at the lipid-water interface of free standing phospholipid bilayers and surface-adsorbed phospholipid monolayers. Fundamental in the theory is that the conformations of lipid molecules are generated with a rotational isomeric state approximation on a lattice and weighted according to Boltzmann statistics where the local self-consistent field potential is computed using Flory-Huggins chi-parameters and averaged contact fractions. Electrostatic energies are also incorporated (in a Poisson-Boltzmann way) into the model so that quite complex molecules, in this case zwitterionic and charged phospholipids, are considered. Results show that lipid head group P-N orientations in phosphatidylcholine (PC) monolayers and bilayers are angled from the layer plane in two probable conformations, whereas the head groups of phosphatidylserine (PS) in PS monolayers and bilayers have only one preferred conformation which is tilted toward the solution. The interaction of potentially permeant cations with the lipid was studied in the presence of screening electrolyte which is present at about 103 times the permeant ions’ volume fraction in solution. Because of the form of the potential profile in both PC and PS layers, bulk electrolyte cations associate electrostatically with the phosphate group in both lipids and to a lesser extent with the carboxyl group in PS and themselves modify the potential profile across the lipid layer. The attraction of cations to the polar groups is greater with negatively charged PS than with zwitterionic PC and increases with the charge of the cation. Although there is a large difference between the potential profiles across monolayers of PC and PS in a monovalent cation 1:1 electrolyte, the difference in potential profiles across the two lipid layers PC and PS respectively is not so great in 2:1 and 3:1 electrolytes. This is reflected in the adsorption of permeant cations at the lipid-water interface.