Complete pulpotomy as a treatment option for caries exposure in mature permanent teeth with complete root formation still remains controversial due to lack of evidence on the long-term success. This article highlights a rare complete pulpotomy case done on a mature permanent tooth that survived for 20 years. A 34-year-old female presented with dull spontaneous pain on her right mandibular first molar and showed positive response to both cold test and electrical pulp test. The tooth was previously restored with tooth coloured restoration at the disto-occlusal surface and pre-operative periapical radiograph revealed large radiopacity covering the entire pulp chamber with calcified canals. The tooth was diagnosed as previously initiated therapy with symptomatic apical periodontitis. Endodontic treatment was initiated. All canals were located and corrected working length achieved followed by cleaning and shaping using HyFlex CM rotary files with copious irrigation of 2.5% sodium hypochlorite solution. Intracanal medication (non-setting calcium hydroxide) was placed and the tooth was restored with temporary restoration. After two weeks, obturation was done using single cone technique with EndoRez sealer. Universal composite resin was placed as permanent restoration and follow-up was done after one month and three months respectively without symptoms and evidence of periapical lesion. This minimally invasive pulpotomy procedure may be an alternative treatment option for mature permanent teeth whenever carious exposure to the pulp occurs.