Aim Comparison of Tanaka Johnston mixed dentition analysis using the mobile photogrammetric method and traditional method. Patients and methods Thirty-five healthy children between the ages of 6 and 10 were signed up for the study. Casts were considered using the conventional Tanaka Johnston analysis method. A digital caliper was utilized to measure the mesiodistal dimension of every tooth from the incisor to the first permanent molar on both sides. Occlusal photos were taken intraorally using a smartphone and an intraoral occlusal mirror. The principal investigator took the intraoral pictures. An assistant retracted the lips and placed the intraoral mirror inside the mouth. The acquired images were exported to the digimizer software, where they were processed and analyzed. To enable digital software to measure dental arch images, an occlusal ruler was kept at the occlusal level. A total of 20 tooth measurements in the maxillary and mandibular arches were taken for the Tanaka Johnston mixed dentition analysis. Results Thirty-five children were assessed. Intergroup comparison of different parameters between two groups was performed. This comparison revealed no statistically significant differences (P value > 0.05) between the traditional and photogrammetric methods for all parameters, indicating that both methods produce similar outcomes. Conclusion The photogrammetric method is a reliable and valid method to measure individual tooth width. The photogrammetric method is alternative to traditional method for Tanaka Johnston mixed dentition analysis.