The molecular organization within multilayers of myelin basic protein (MBP) and acidic phospholipids was investigated. The samples were prepared by Langmuir-Blodgett transfer of protein/lipid precursor Langmuir films from the air/water interface after binding of MPB from the subphase. The presence of MBP within the multilayer was directly proven by Fourier transform infrared spectroscopy (FTIR) and circular dichroism (CD) measurements. The CD measurements indicated a partially ordered secondary structure of the protein in the multilayer, in contrast to its random coil configuration in the bulk. X-Ray reflectivity measurements revealed vertically well ordered multilayers with the protein located within well defined slabs between the lipid headgroups of the individual bilayers of the samples. These slabs consisted of protein, lipid headgroup moieties, ions, and water molecules, each of which is of importance for the molecular organization of the multilamellar stacks. By combining X-ray and neutron reflectivity techniques and by in-situ exchange of the H2O by D2O within the multilayers, the presence of water within the protein slab was proven and its amount was estimated. The results demonstrate, that, under controlled environmental conditions, the organization of the proteo-lipid multilayers at the planar interface can be elucidated to detail. Hence, the supported MBP membranes investigated here can serve as valuable model systems for the natural myelin sheath.