Films of purified bovine rhodopsin were deposited using the Langmuir-Blodgett (LB) technique. The area occupied by a molecule of rhodopsin in a monolayer was calculated to be about 10(3) Angstrom(2) from nanogravimetric measurements. The periodicity of the multilayer obtained from small-angle X-ray scattering was 61 Angstrom. Circular dichroism measurements showed that rhodopsin in the LB films acquired a high thermal stability, reaching a temperature of 150 degrees C in the light and 200 degrees C in the dark without loss of the secondary structure. The multilayers of rhodopsin retained the characteristic absorption peak at 500 nm, which did not bleach in the light, but was reversibly converted to a maximum absorption at 480 nm typical of the intermediate metarhodopsin I. Moreover, the absorption maximum of rhodopsin in the film at 500 nm was retained up to about 90 degrees C.