This paper reports on a new surface treatment, coupling phosphates on alumina surfaces for bioactivation. Alumina samples were treated in monoaluminumphosphate solution at 1400 degrees C. Strongly coupled aluminum phosphates due to the treatment were proved by X-ray diffraction and infrared spectroscopy. Contact angle measurements proved the hydrophilic nature of the treated surface. In vitro tests in simulated body fluid indicated a bioactive behavior by means of apatite-forming ability. Such functionalized alumina ceramics imply the potential for a new class of bioactive high-strength ceramic implant materials, due to a pronounced affinity of bioactive phosphate groups to particular amino acid sequences of proteins.