Objective: The purpose of this study was to evaluate the accuracy of full-arch scans using 11 different cast scanners. Method and Materials: Dental arch length (AL), intermolar width (IMW), and intercanine width (ICW) of the reference plaster casts were measured using a coordinate measuring machine (Zeiss O-Inspect 422). The master cast was subsequently scanned 37 times using 11 desktop scanners (3Shape R500, 3Shape R700, 3Shape R1000, 3Shape R2000, Medianetx grande, Medianetx colori, DentaCore CS ULTRA, Dentaurum OrthoX, Maestro 3D, Imetric IScan D104i, GC Aadva Lab Scan). Using the software Convince Premium 2012 (3Shape), AL, IMW, and ICW were measured on the digital models and compared to the reference plaster cast. Results: The accuracy of the cast scanners differed significantly. The most accurate measurements were given by the cast scanners 3Shape R700 (ICW: 7.4 ± 5.9 µm) and Imetric IScan D104i (ICW: 9.1 ± 4.9 µm). The cast scanners 3Shape R1000 (ICW: 11.2 ± 3.4 µm) and GC Aadva Lab Scan (ICW: 13.8 ± 8.1 µm) yielded comparable measurements. DentaCore (ICW: 26.6 ± 7.5 µm) and Dentaurum OrthoX (ICW: 31.1 ± 24 µm) were significantly less accurate. Conclusion: Almost all scanners demonstrated a level of accuracy so high that further improvement would not provide additional benefit for use in orthodontics. Advancement of the scanners should focus primarily on reducing time and cost. For prosthodontic use, the scanners with the highest accuracy are recommended. Keywords: accuracy, CAD/CAM, desktop scanner, digital model, full-arch scan, plaster cast