Introduction: Estimating the mesiodistal widths of unerupted permanent canines and premolars is an essential aspect of mixed dentition analysis. Several methods are used to predict tooth width. The best methods demonstrate high values of correlation and determination coefficients. Aim of Study: The objectives of this study were to determine linear regression equations that would predict the sum ofthe mesiodistal widths of permanent canine and premolars based on the sum of the widths of the four permanent incisors and first permanent molars for Egyptian population. Methods: The sample consisted of one thousand dental casts obtained from Egyptian subjects, (five hundred males and five hundred females) their age ranged from 18 to 22 years old with mean age 20 years. Mesiodistal tooth widths were measured with an electronic digital caliper. Intraclass correlation coefficientswere used to determine measurement consistencies. Paired and unpaired Student tests were used to determine right/left side and sex differences, respectively. A paired Student test was also used to compare the predicted and actual sums of the permanent canine and premolars. Results: We found high values of correlation (r) and determination (r2) coefficients. These values are among the highestdescribed in the literature for non-radiographic prediction methods. There were no statistically significant differences between right/left sides and found statistically significant differences between the mesiodistal widths of teeth between the sexes in arches. Males had significantly larger teeth than females except of the maxillary lateral incisors and first premolars teeth where there was no statistically significant difference. There was no difference between predicted and actual widths of the permanent canine , first and second premolars. Conclusions: The new equations showed reliable and easy to use for prediction the widths unerupted canine, first and second premolars for Egyptian population. But it must be tested in otherpopulations.