The authors measured the precementation space achieved in vivo with varying layers of die spacer. Two hundred and ninety-one castings were fabricated in the Advanced Education Program in Prosthodontics at New York University College of Dentistry, New York, New York. Each of four clinician groups applied one layer of Taub Die Hardener and from one to four layers of die spacer to within 0.5 to 1.0 mm of the dies; finishing line. The resultant castings were adjusted using GC Fit-Checker. After final seating of the casting, the Fit-Checker was removed, sectioned buccolingually, and measured using a micrometer at three locations (midocclusally, midaxially, and on the bevel) for a total of 657 readings. Only after data collection were the specimens identified by group. Analysis of variance demonstrated a significance for group and location. Post hoc one-way analysis of variance and Sheffe tes ts (P .1) demonstrated that: (1) one or two layers of die spacer demonstrated smaller precementation spaces than three or four layers; (2) the midocclusal precementation space was greater than the midaxial precementation space; (3) on the bevel area where no die spacer was used, the most consistent and minimal precementation space was measured.