Aim:To evaluate the applicability of the Tanaka and Johnston (1974) and Moyers (1988) methods in predicting the size of permanent canines and premolars in Chennai school children.Materials and Methods:470 sets (127 female and 343 male) of cast models were included in the sample. Mesio-distal (m-d) widths of all teeth from left to right first molars were measured and compared with the predicted values derived from Tanaka and Johnston and Moyers methods.Results:There was significant bilateral symmetry and sexual dimorphism in teeth sizes seen in both the sexes. Sum of the m-d diameter of permanent mandibular incisors can be used reliably to predict the sum of m-d diameters of unerupted canines and premolars.Conclusions:Tanaka and Johnston's method cannot accurately predict the m-d widths. Moyers’ prediction tables can be used to estimate the m-d widths of unerupted canines and premolars closer to 50% probability level.