Objectives: The aim of this study is to evaluate the efficiency of R-Endo Retreatment System and hand files for the removal of filing material during root canal retreatment and to evaluate the influence of the irrigation regimens and sealer types on the adherence of filling debris in the reinstrumented canals. Material and methods: Eighty freshly extracted human single-rooted teeth were instrumented with K-files and randomly divided into two groups of 40 specimens each were irrigated with 3ml of 5.25% NaOCl followed by 3ml of 17% EDTA or with 3ml of 2% CHX. Then each group divided into two subgroups of 20 specimens each were filled with GP/AH Plus sealer or filled with GP/iRoot SP sealer. According to retreatment method, each subgroup was further subdivided into two subgroups of 10 specimens each were R-Endo or Gates-Glidden drills and H-Files used. Times to eliminate filling material were recorded. Root canal walls were examined using SEM and stereomicroscope to evaluate material remnants on each third of both halves. The Student’s t-test was used to determine significant differences between mean values of time and remaining material (P ≤ 0.05). Results: None of the techniques completely removed the root filling materials. The R-Endo subgroups had less filling material inside the root canals than the other groups but with no significant difference (P ≥ 0.05). Apical third of all subgroups showed significantly more remnants than middle and coronal thirds (P ≤ 0.05). However, times for removal of filling were lower with R-Endo than with Hedström files (P ≤ 0.05). Conclusion: Both instrumentation techniques left filling material inside the root canal and mainly in the apical third. There was no difference between the instrumentation techniques.