The marginal adaptation of fired ceramic inlays prepared by three dental technicians in two ceramic materials was evaluated in vitro. The thickness of the sealing gap varied between 46.4 and 57.6 um, and the percentage of margina l ceramic defects ranged between 8.6% and 25.0% of the total inlay circumference. The incidence of marginal defects increased in areas of complex occlusal morphology. Dif ferences observed in inlay adaptation were realted to the technician rather than to the material used. The accuracy of ceramic inlays was comparable to that of metallic and porcelain-fused-to-metal crowns with butt-joint margins and fell within the range of clinically acceptable adaptation.