Rationale: Dental arch dimensions are not static; they change systematically during the period of intensive growth and development and less so in adulthood. Objectives: To assess maxillary and mandibular dental arch dimensions of the Saudi population. Methods: Alginate impressions were made of the maxillary and mandibular dental arches of 100 male and female subjects aged between 20-28 years to obtain study casts. The dental cast analysis was done to measure arch widths, arch lengths and palatal depths using Boley__ampersandsignrsquo;s guage by a standardized method. The measurements of maxillary and mandibular arch dimensions were tabulated and analyzed using independent test and Pearson__ampersandsignrsquo;s correlation test. Results: Male gender showed increased arch dimensions in both maxillary and mandibular arches as compared to females. The difference was found to be statistically significant except for maxillary anterior and molar arch lengths. A strong positive correlation (r=0.8, p__ampersandsignlt;0.05) was observed between maxillary inter canine width and total arch length among females. Conclusion: The determined maxillary and mandibular dental arch dimensions are useful in selecting accurate stock impression tray, selection and arrangement of artificial teeth among Saudi edentulous patients undergoing prosthetic rehabilitation.