The implantation at elevated temperatures of Co into single-crystal BaTiO3 (K), SrTiO3, or KTaO3 (Ca), followed by annealing at 700degreesC, produced ferromagnetic behavior over a broad range of cobalt concentrations. For BaTiO3, this process produced magnetic ordering temperatures above 300 K with coercivities less than or equal to70 Oe. The magnetization-temperature (M-T) plots showed a near-linear decrease of magnetization with increasing temperature. No secondary phases were detected within the sensitivity of high-resolution X-ray diffraction. Similar results were observed for both SrTiO3 and KTaO3. Our results are consistent with recent reports of room temperature ferromagnetism in other perovskite systems such as LaBaMnO3 and theoretical predictions for transition metal doping of BaTiO3. (C) 2003 The Electrochemical Society.