Multilayer structures, consisting of successive lysozyme layers and layers of iodide and potassium ions, have been formed on a silicon substrate by the modified Langmuir–Schaefer method; the use of this technique implies preliminary preparation of a crystallization protein solution containing an oligomeric phase. The multilayer structure has been characterized by methods of X-ray reflectivity and total external reflection X-ray standing waves (TER XSW). The data obtained indicate the formation of a dense lysozyme film (3 nm thick) and layers of potassium and iodide ions, adjacent to this film.