Background: Untreated progressive inflammatory periodontal disease can affect attachment loss until bifurcation or trifurcation of multirooted teeth. Hemisection in multirooted is removal of compromised root preserve the good one then restorative coronal part with a fixed prosthesis. It is the treatment option for preserving the remaining part of healthy root who having sound periodontium. The study aimed to describe a case of a hemisection is presented for a tooth where only the mesial root of a mandibular molar was affected.Case presentation: a 22 years old female comes to RSGM Prof. Soedomo with moderate pain and gum swelling. Perforation in mesial root canal wall in the objective examination. In radiograph, there were radiolucent in mesial root, bifurcation and fracture instrument left in mesial apical root canal. The conditions that can't approach in non-surgical treatment such as fracture instrument, severe vertical bone loss, caries, internal or external resorption in furcation or one root, and furcation lesion, can be treated with surgical approach hemisection as alternative before axtraction teeth. Hemisection treatment includes root canal treatment of the remaining roots, intracanal retention with fiber post then restorative the coronal part use restorative material and splinting with the adjacent tooth to decrease the risk of displacement. Fixed prosthodontic prosthesis to maintain the occlusal balance.Conclusion: hemisection is a feasible treatment option because more practical and conservative for periodontal-endodontic lesions rather than extraction teeth.