This study aimed to examine the applicability of the pulp/tooth ratio (PTR) method for age estimation in Mongolian populations using panoramic radiographs and derive new regression formulae. Moreover, we aimed to assess the accuracy of these formulae in other subjects from the Mongolian population and compare them with the other formulae derived from different Asian populations. The total sample size of the study was 381. The formulae were derived from the examination of panoramic radiographs of 271 individuals aged 15-62 years. Following Cameriere's method, PTR was calculated for the upper and lower canine teeth. Linear regression analyses were performed between the actual age and that obtained from upper-lower canine PTR and established formulae for age estimation. To verify the formulae, two types of test samples were collected: 73 panoramic radiographs and 37 periapical radiographs. The estimated age was calculated using our new formulae and three other formulae derived from Asian populations. The correlation coefficient between the actual age and that obtained by PTR was significantly negative for both canines. According to our new regression formulae, the differences between the estimated age and actual age showed a bell-shaped curve distribution in both test groups. While using the other formulae derived from the Asian population, the distribution patterns obtained were significantly different in the Mongolian population. This study was the first to examine the relationship between actual age and PTR in Mongolian population, and these results advance the field of forensic science in Mongolia.