Titanium is well known as an implant material having excellent biocompatibility and mechanical properties for use in bone substitute. In the present study, to enhance the biocompatibility of titanium, its surface was modified by hydrothermal treatment using dilute alkaline solution. After hydrothermal treatment, anatase predominantly formed on a titanium surface. The anatase phase showed high crystallinity and c-axis orientation. The anatase layers with leaf-like and pyramid-like forms were observed on titanium autoclaved at 120 °C and 240 °C, respectively. The anatase formation and its morphology were significantly related to the autoclaving temperature. To estimate the cellular compatibility of the autoclaved titanium, mouse osteoblast-like cells (MC3T3-E1 cells) were cultured on the autoclaved titanium surface. After 7- days culturing, the number of the cells harvested from the autoclaved titanium was higher than that from untreated titanium. The surface modification of titanium by hydrothermal treatment involved the proliferation of the cells on its surface.