Aim: To assess the root canal preparation with the rotary Protaper. To evaluate the efficacy of enginedriven Protaper files in shaping the canal. Objectives and Methods: A total of 50 molars with closed apical foramen (exclude the third molars) which need endodontic treatment were selected in the endodontic department of the National hospital of Odonto-Stomatology from April to December 2011. This is a follow-up study. Results: Average time required to complete the preparation is 45.54 + or - 14.25 minutes.About the sequels, 3 percent perforation, 6 percent broken instruments. About the results, 92 percent obturation to the apex, 92 percent has no symptom after obturation 1 week, the success rate after 3 to 9 months is 87.23 percent. Conclusion: The rotary protaper can cut dentin and shaping canal effectively, less time required to complete canal shaping in comparision with hand-operated instruments. Root canal preparation with Protaper manual instruments is easily manual, less step and suitable for experienced doctors. Proper preparation limits procedural errors and their sequel. The success rate is 87.23 percent.