Abstract: Objective To evaluate the shortterm clinical efficacy of CEREC AC chair side immediate allceramic restorations. Methods 82 defective teeth from 59 patients were collected and CEREC AC was used to make immediate allceramic restorations including 21 inlays,30 onlays,8 veneers and 23 crowns.The milling time was recorded and the clinical efficacy was analyzed with modified USPHS criteria in 3 and 6 months. Results The average milling time was less than 9 minutes.Most of the restorations scored A using modified USPHS criteria. Conclusions CEREC AC system chair side immediate allceramic restorations can obtain satisfactory shortterm clinical outcomes.