The aim of the study was To collect normative data of crown size of primary dentition in a group of Yemenis Children and Compare the results we were found to previous published data of other Arab populations. Subjects and methods: A total number of two hundred Yemeni children were included in this study, 100 males and 100 females, their ages ranged from 3-7 years old. Upper and lower impressions were taken. Each impression was poured immediately in stone plaster. A full set of primary teeth (incisors, canines, first and second molars) on both sides of the maxillary and mandibular dental arches were measured in Mesiodistal (MD) dimension. Results: No statistically significant difference in the mean mesiodistal tooth width between the mesiodistal crown size obtained in the present study with those reported by other authors who studied other Arab populations. Conclusions: The present values were numerically greater than, but close to the values obtained in Egyptian children, where all deciduous teeth were also evaluated. In Jordanian population that revealed largest mesiodistal value in comparison to the Egyptian and our study of Yemenis children.