Introduction: During othodontic treatment planning, accurate space analysis is very important in this period. The present study was planned to determine the mesiodistal widths of lower permanent canines and premolars from Tanaka-Johnston, Moyers ’and Bernabé E & Flores-Mir C mixed dentition analysis; to determine the correlation coefficients and the new prediction equation for Sri Ganganagar population. Materials and method: 100 children aged 11-16 years of Jammu city were randomly selected. The mesiodistal width of permanent incisors, canines, premolars and molars was measured with the help of digital vernier caliper with an accuracy of ±0.01mm. The measurements of canines and premolars were summed up and compared with those derived from Tanaka and Johnston equations, Moyers probability tables and Bernabé & Flores-Mir equations. Results: All the three methods overestimated the actual sum of permanent canine and premolars in both the arches in our population. Conclusion: The predicted values obtained from all the three methods overestimated the actual values. Results derived are more clinically appropriate and reliable for the prediction of tooth size of unrupted permanent canines and premolars, to determine the discrepancy between the available and required space in the dental arch. As this equation is limited only to the city population of school going children, further studies are required incorporating large population size to draw appropriate results.