This research emerged as a part of a project applied on different Egyptian cities to collect data regarding mesiodistal widths of the permanent mandibular incisors, maxillary and mandibular canines and premolars in a group of Egyptian children and adolescents in Al Qalyubiyah Governorate, as most data available are for Northern European children and only little data are available for Egyptian population. Objectives: To determine the mesiodistal widths of the permanent mandibular incisors, maxillary and mandibular canines and premolars in a group of Egyptian children and adolescents in Al Qalyubiyah governorate and to correlate between the combined mesiodistal widths of the teeth under study. Methods: Asample of 280 schoolchildren and adolescents (140 males and 140 females) with an age range from 12-15 years in Al Qalyubiyah governorate. Results: The results of this study revealed that; (1) No statistically significant difference in the mean mesiodistal tooth width between right and left sides in all teeth under study; (2) Teeth of males were significantly larger than those of females except for lower right second premolar; (3) Positive correlations were found between mesiodistal teeth width of mandibular incisors and maxillary and mandibular canines and premolars. Conclusion: The mesiodistal widths of upper and lower canines and premolars can be predicted by measuring the mesiodistal width of lower incisors.