Introduction: Treatment planning is crucial for proper tooth alignment in a mixed dentition stage. An examination of the mixed dentition should be able to predict the mesiodistal widths of the unerupted permanent teeth. Overestimating of width for unerupted teeth could increase the space required and lead to unnecessary extractions. Design: Cross-sectional study. Participants: This study included 307 subjects (148 males and 159 females) aged from 16 to 22 years. Material and methods: Digital Vernier calipers was used to measure Mesio-distal tooth width on study cast Measurements of the predicted width of canine and premolars according to Moyer's prediction tables were compared with the measured values on plater models. Results: No statistically significant difference in measured width of upper and lower canine and premolars (UCPM, LCPM, respectively) in male vs. female. Poor reliability (ICC<0.5) for all measures in comparison with the predicted values except for 50th percentile for females in lower canine & premolars which was moderate (ICC =0.534). Conclusions: The Egyptian population is not consistent with Moyer's prediction tables.