Introduction: Moyers__ampersandsignrsquo; mixed dentition space analysis is the most commonly used analysis to detect the tooth size-arch length discrepancy in patients with mixed dentition. At the same time Moyers__ampersandsignrsquo; method of prediction is said to have population variations. Aim: The present study aimed to evaluate the applicability of Moyers__ampersandsignrsquo; mixed dentition probability tables in the South Indian population and to frame a new regression equation to predict the sum of mesiodistal tooth widths of the permanent canine and the premolars. Methods: Mesio-distal tooth measurements of teeth were measured using digital vernier calliper from the study models of 50 orthodontic patients. The tooth sizes were compared between males and females using statistical analysis. The new regression equation was formulated from the standard linear regression equation y=a+bx, where a and b are constants, x is the sum of the mesiodistal width of mandibular incisors and y is the sum of widths of canine and premolars. Results: __ampersandsignbull; There was no significant difference between the tooth sizes of the males and females according to the data collected from the current study sample. __ampersandsignbull; TMoyers__ampersandsignrsquo; prediction tables are not suitable for predicting the mesiodistal widths of the unerupted canine and premolars in the South Indian population. Conclusion: New linear regression equations were formulated separately for males and females, to predict the sum of mesiodistal width of unerupted canine and premolars, using the sum of mandibular permanent incisors. The following are the new prediction equations: Males: Maxilla-8.50 + 0.57 (X) Mandible-6.06 + 0.64 (X) Females: Maxilla-2.08 + 0.84 (X) Mandible-7.25 + 0.59 (X), where X is the sum of the mesiodistal width of mandibular permanent incisors.