The formation and time evolution of TiO islands on SrTiO3(001) surface facets at 970 degrees C are studied by in situ high-resolution transmission electron microscopy (HRTEM). The exact surface morphology of the islands and the interface between the islands and the SrTiO3 bulk are characterized by profile imaging in cross-section. At the initial stage of formation, the islands contain crystal defects which disappear after annealing times for longer than 100 min. Lattice parameter measurement from the HRTEM images reveals that the crystal islands may be identified as TiO. They are faceted in shape, having the {001} and {011} facet components. During annealing for about 2.5 h the islands grow to sizes of 3-4 nm in equivalent sphere radius, and shrink again during longer annealing. The interface between the TiO islands and the SrTiO3 bulk also shows faceting.