Mechanical activation, without any additional heat treatment, is used to trigger the formation of a perovskite BaTiO3 phase in an oxide matrix that consists of BaO and TiO2 in a nitrogen atmosphere. The resulting BaTiO3 powder exhibits a well-established nanocrystalline structure, as indicated by phase analysis using X-ray diffractometry. A crystallite size of similar to 14 nm is calculated, based on the half-width of the BaTiO3 (110) peak, using the Scherrer equation, and an average particle size of 20-30 mm is observed using transmission electron microscopy for the activation derived BaTiO3 powder.