A novel high-k cobalt-titanium oxide (CoTiO3) was formed by directly oxidizing sputtered Co/Ti film. Al/CoTiO3/Si3N4/Si capacitor structure was fabricated and measured. The effective dielectric constant with buffered layer for CoTiO3 gate dielectric can reach as high as 40 while depicting excellent electrical properties at the same time. This novel metal oxide thus appears to be a promising high-k gate dielectric for future ultralarge scale integrated devices.