Objective: The clinical performance of IPS Empress (Ivoclar Vivadent) inlays and onlays was evaluated at 6 years. Method and Materials: Sixty-four porcelain inlays and onlays were placed in 29 patients, aged 21 to 70 years, by a single operator using the same clinical procedure. The restorations were examined for fracture rate; esthetics; patient acceptance; and marginal integrity, including caries, marginal discoloration, and gingival tolerance. All restorations were evaluated at the time of placement and at 1, 2, 4, and 6 years after placement. Results: At 6 years, 93.7% of the restorations were judged clinically acceptable. The fracture rate was very low (3.1%), patient satisfaction was encouraging, and the maintenance of esthetics was superior. However, marginal discoloration and integrity appeared to deteriorate with time, because of loss of marginal seal and dissolution of the luting agent. Conclusion: IPS Empress ceramic inlays and onlays are clinically acceptable. However, a disadvantage is the dissolution of the resin matrix of composite resins in oral fluids. Keywords: ceramic inlay, ceramic onlay, clinical performance, esthetics, IPS Empress system, marginal discoloration