A novel instrument has been developed for depositing Langmuir–Blodgett (LB) films composed of alternating molecular monolayers of amphiphilic molecules and adsorbed layers of soluble compounds. The main feature of the deposition method is the possibility to prevent the transfer of the monolayer onto the substrate when dipping up. This can be achieved by keeping the external boundary of the deposited monolayer in contact with the aqueous solution by means of a protecting hydrophilic plate which covers the substrate with the film while still immersed in water. After that, the plate is fixed to the substrate parallel to its surface and both can be transferred to other compartments of the instrument for adsorption of soluble compounds onto the active hydrophilic surface or for deposition of monolayers of other types. Principal design elements, electronics, and software of the LB instrument based on this principle are described. Results on the deposition of LB films composed of alternating monolayers of amphiphilic donor molecules of hexadecylbis(ethylenedithio)tetrathiafulvalene and adsorbed layers of the soluble protein cytochrome P 450sccare reported as an example of the device functioning. ©1996 American Institute of Physics.