Stable nanoparticulate TiO2-stearate (TiO2-St) monolayers can be obtained by using TiO2 (anatase-type) hydrosol as the subphase. The area extrapolated to pi = 0 is 0.25 nm(2) per hydrocarbon chain of the monolayer. The "collapse" pressure is about 50 mN m(-1). The monolayer can be transferred onto a solid substrate perfectly under certain pressure. The surface of the even-layer (odd-layer) of the multilayer is apparently hydrophilic (hydrophobic). This implies that the nanoparticle and the hydrocarbon chain exist in an alternating structure. The Fourier transform infrared spectrum of the films revealed that stearic acid is converted to the stearate ion almost completely and chemical bonds were formed between TiO2 and stearate ions. The long CH2 sequence of the hydrocarbon chains of the multilayer is in an ordered structure. The long spacing of the multilayer determined by X-ray diffraction is 12 nm. The surface coverage of TiO2 nanoparticles is commonly concentrated observed by transmission electron microscopy. The results show that perfect Langmuir-Blodgett-type multiparticulate layers have formed.