To examine the applicability of the Tanaka & Johnston method of prediction and to find the significant difference in Pakistani population. Comparative cross sectional study. The study was conducted at Karachi Medical & Dental College, Karachi, from September 2001 to September 2003. The 300 study dental plaster casts of Pakistani subjects under the age of 21 years, who presented with complete eruption of permanent mandibular incisors, canines and premolars, as well as maxillary canines and premolars were measured. The measuring device was a modified Boley`s gauge. The sampling technique was non probability with a comparative. study design. Statistical analysis was made by using SPSS version-10. Descriptive statistics was used for data presentation. Students t- test and test of linear correlation was used for testing the null hypothesis. Level significance was taken at p