Nonsurgical retreatment involves removing mechanical barriers such as gutta-percha to achieve proper cleaning and disinfection. The complexity of the anatomy of molar tooth gives challenge in retreatment procedure. Thus, this study evaluates the amount of residual gutta-percha after retreatment with rotary files (Reciproc Blue®) from each maxillary first molar canal using cone-beam computed tomography (CBCT) and the time required to accomplish it. Nine freshly extracted maxillary molars were instrumented and obturated. Preoperative CBCT was taken, and retreatment was done using Reciproc Blue®. CBCT was taken post retreatment, and the residual volume percentage of gutta-percha from each canal was calculated. The total retreatment time was recorded, and the data were statistically analyzed. The result shows no statistically significant difference in the amount of residual filling material in mesiobuccal, distobuccal, and palatal canal for maxillary first molar and total time used for retreatment with Reciproc Blue® system.