Sodium aluminophosphate glasses were evaluated for their bone repair ability. The glasses belonging to the system 45Na(2)O-xAl(2)O(3)-(55-x)P2O5, with x=(3, 5, 7, 10mol%) were prepared by a melt-quenching method. We assessed the effect of Al2O3 content on the properties of Na2O-Al2O3-P2O5 (NAP) glasses, which were characterized by density measurements, DSC analyses, solubility, bioactivity in simulated body fluid and cytocompatibility with MG-63 cells. To the best of our knowledge, this is the first investigation of calcium-free Na2O-Al2O3-P2O5 system glasses as bioactive materials for bone tissue engineering.