There is a close relationship between endodontic and periodontal tissue structures. This relationship affects the spread of infection and the prognosis of endodontic-periodontal lesion. Pulpal disease may induce periodontal destruction and vice versa. In general, the prognosis of primary endodontic lesion with secondary periodontal involvement is favorable to excellent after adequate endodontic treatment, even no periodontal treatment is rendered except supragingival scaling. This report presents two cases of primary endodontic lesion with secondary periodontal involvement which demonstrates good clinic results after long-term follow up.