The pulp and the periodontal attachment are the two components that enable a tooth to function in the oral cavity. Lesions of the periodontal ligament and adjacent alveolar bone may originate from infections of the periodontium or tissues of the dental pulp. The simultaneous existence of pulpal problems and inflammatory periodontal disease can complicate diagnosis and treatment planning. The function of the tooth is severely compromised when either one of these is involved in the disease process. Treatment of disease conditions involving both of these structures can be challenging and frequently requires combining both endodontic and periodontal treatment procedures. This article presents cases of periodontitis associated with endodontic lesions managed by both endodontic and periodontal therapy.