The purpose of this study was to determine whether cone beam digital models are as accurate as OrthoCAD (Cadent, Inc, Carlstadt, NJ) digital models for the purposes of orthodontic diagnosis and treatment planning. Digital records of 30 subjects were retrospectively reviewed, and the digital models were obtained as OrthoCAD and InVivoDental (San Jose, CA) digital models. Seven parameters indicating linear measurements from predetermined landmarks were measured and analyzed. The analysis of variance and Bland and Altman Analysis were used to compare and evaluate measurements made from the study models generated from cone beam computed tomography (CBCT) and InVivoDental software. The mean difference between the maxillary InVivoDental models and the maxillary OrthoCAD models ranged from -0.57 to 0.44 mm. The analysis of variance for repeated measures (P < 0.001) was applied to all data obtained from the CBCT and OrthoCAD models. The results indicated a mean score of 35.12 and 35.12 mm, respectively. The mean difference of all values was -7.93 - 10-3 mm. The range of these values at the 95% confidence interval was -0.14 and 0.12 mm for the lower and upper limits, respectively. The results were not statistically significant for both groups. The Bland and Altman analysis was also applied to the data. In the maxilla, the results indicated that the mean difference between InVivoDental and OrthoCAD was -0.01± 1.24 mm. The range of the analysis indicated a spread of -2.40 mm and +2.40 mm. In the mandible, the results indicated that the mean difference between InVivoDental and OrthoCAD was -0.01 ± 1.21 mm. The range of the analysis indicated a spread of -2.36 mm and +2.37 mm. The results showed that the linear measurements obtained from CBCT image casts indicated a good level of accuracy when compared with OrthoCAD models. The accuracy was considered adequate for initial diagnosis and treatment planning in orthodontics. © 2011 Elsevier Inc.