An approach for the preparation of patterned ultrathin TiO2 films is demonstrated by using phase-separated Langmuir monolayers, wherein the mixed monolayer of long-chain alkylamine and perfluoroalcohol is formed on an aqueous subphase containing potassium titanium oxalate, followed by deposition onto a solid substrate as a single-layer Langmuir-Blodgett (LB) film. Atomic force microscope observation of the LB films shows that ring-like TiO2 domains are formed on the surface of the substrate and that the size and shape of the TiO2 domains can be tuned by concentration of spreading solution as well as mixing ratio of the two film materials. Subsequent heat-treatment at 500 degrees C results in TiO2 films of 1.6 nm in thickness maintaining the ring-like pattern.