Hemisection of a molar denotes removal or separation of a root along with its accompanying part of crown. It is a suitable treatment option when the caries, resorption, perforation, or periodontal damage is restricted to one root while the other root is relatively healthy. Hemisection of the affected tooth helps to retain the tooth structure, surrounding alveolar bone, and may also facilitate the placement of fixed prosthesis. This case report describes the hemisection as a successful treatment method to save a grossly carious mandibular first molar with periodontal and periapical involvement. Hemisection and prosthetic rehabilitation yielded a satisfactory result. With careful treatment planning and precise surgical management, undesirable consequences of tooth loss were prevented.