Purpose: The objective of this follow-up study was to examine the performance of Cerec inlays and onlays in terms of clinical quality over a functional period of 10 years. Materials and Methods: Of 200 Cerec inlays and onlays placed in a private practice between 1989 and early 1991, 187 restorations were observed over a period of 10 years. The restorations were fabricated chairside using the Cerec-1 computer-aided design/manufacturing (CAD/CAM) method and Vita MK I feldspathic ceramic. An adhesive technique and luting composite resin were used for seating the restorations. After 10 years, the clinical performance of the restorations was evaluated using modified USPHS criteria. The results were used to classify success and failure. Results: According to Kaplan-Meier analysis, the success rate of Cerec inlays and onlays dropped to 90.4% after 10 years. A total of 15 (8%) failures were found in 11 patients. Of these failures, 73% were caused by either ceramic fractures (53%) or tooth fractures (20%). The reasons for the remaining failures were caries (20%) and endodontic problems (7%). The threesurface Cerec reconstructions were found to have the most failures. Conclusion: The failure rate of 8% and the drop of the survival probability rate to 90.4% after 10 years of clinical service of Cerec-1 CAD/CAM restorations made of Vita MK I feldspathic ceramic appear to be acceptable in private practice. This is particularly true in light of the very high patient satisfaction.