Background: Clinical success of endodontic treatment occurs when the tooth is painless, firm, non-mobile, and without any signs of inflammation or infection. Radiographically, lesions should be resolved within six months, and no pathologic root resorption should be observed. Traditional endodontic treatment technique was done by hand instrumentation. Initially, the endodontic files were made with carbon steel that was susceptible to fracture, tarnish, and corrosion, so stainless steel files were introduced. Soon the nickel–titanium (NiTi) files became popular. Aim of the study: To compare effectiveness of canal preparation and canal debridement by hand files and rotary files. Materials and methods: The present study was conducted in the Department of Endodontics of the Dental institution. For the study, a total of 100 extracted first premolars were selected. Only non-carious teeth, with no signs of root resorption and absence of any structural abnormality were selected for the study. The teeth were randomly grouped into two groups, Group A and Group B with 50 teeth in each group. The instrumentation of specimens of the Group A was done using stainless steel K-files and in Group B was done using Mtwo NiTi rotary files. Results: In the present study, we evaluated effect of instrumentation for endodontic treatment by K files and M-two rotary files. We observed that both the file systems are fairly good in canal preparation and canal debridement. On comparing both the systems, M-two files had better results in apical, middle and coronal regions. Conclusion: Within the limitations of the present study, it can be concluded that hand K files and Mtwo rotary files provide satisfactory results for canal debridement and canal preparation. Mtwo rotary system was found to be more effective in canal preparation at apical, middle and coronal region.