Due to their attractive mechanical properties, bioinert ceramics are frequently used in the high load-bearing sites such as orthopaedic and dental implants, but they are chemically inert and do not naturally form a direct bond with bone and thus are lack of osseointegration. A CO2 laser was used to modify the surface properties of bioinert zirconia with the aim to achieve osseointegration between the material and bone. Higher wettability characteristics generated by the CO2 laser treatment was primarily due to the enhancement of the surface energy, particularly the polar component, determined by way of microstructural changes. An in vitro test using human fetal osteoblast cells (hFOB) revealed that osteoblast cells adhere better on the laser treated sample than the untreated sample. The change in the wettability characteristics could be the main mechanism governing the osteoblast cell adhesion on the YPSZ.