statement of Problem: Cleaning and shaping of the root canal system is an important objective of root canal therapy. Many automatic devices have been produced to simplify the preparation, and to decrease instrumentation time. One of these automatic devices with the general name of Endogripper is the new reciprocal handpiece called TEP-E10R.Purpose: The purpose of this study was to compare hand and rotary reciprocal techniques in incidence of change in canal centring of the root canal.materials and method: In this invitro study, 60 extracted mesial roots (120 canals) of human mandibular first and second molars were selected. The mesial roots were mounted in a metallic muffle. Sixty specimens were divided into four groups, (each group consisted of 30 canals). Each root was sectioned in two horizontal directions, the first cut was made five mm from the apical and the latter cut was made in the middle area of the root. The sections were photographed before instrumentation and then were reassembled in the metallic muffle and instrumented. In group one the preparations were made by NiTi files with hand instrumentation. In group two the preparations were made by stainless steel files with hand instrumentation, while in group three the preparations were made by Ni Ti files with use of TEP-E10R reciprocal handpiece, and in group four the preparations were made by stainless steel files and use of the same handpiece as in group three. After instrumentation, the metallic muffle was disassembled and the sections were photographed for the second time after preparation. The pre and post instrumentation photographs were superimposed using Adobe Photoshop and the canal center displacement in each section was measured. The collected data were analyzed with ANOVA and Tukey statistical tests.Results: All specimens in the four groups showed canal center displacement. Group two had the most mean of canal center displacement in coronal sections which was significantly different from group one (p=0.008). In the middle sections, the highest mean of canal center displacement was seen in group four and it was significantly different from group one (p=0.001). In the apical sections, group two had the highest mean of canal center displacement which was significantly different from other three groups (p<0.001).Conclusion: Canal preparation with reciprocal handpiece (TEP-E10R) was similar to hand preparation technique with Ni Ti files in shaping of the root canal system.Key words: Canal centring, Hand instrumentation technique, Rotary reciprocal technique