Zn2TiO4 and TiO2 in the ZnO-TiO2 system have been reported to coexist in the composition region of 33 to 100 mol% TiO2 at temperatures between 1218 and 1691 K. In the present study, compounds prepared by annealing raw materials of ZnO and TiO2 in a molar ratio of 3:2 at 1623 K were studied by high-resolution analytical transmission electron microscopy (TEM). An unexpected precipitate within the spinel-type Zn2TiO4 matrix was found. Viewed along the [001] orientation of Zn2TiO4, the precipitate was found to have a rectangular shape and to be about 40 nm in size, The chemical formula of the precipitate is estimated to be ZnTiO3. Diffraction patterns from the precipitate can be indexed by considering a cubic unit cell with the same lattice constants as that of Zn2TiO4. The orientation of the precipitate with respect to the matrix is [010](100)(pre)//[010](100)(mat), where the subscripts pre and mat represent the precipitate and matrix, respectively.