Aim: To explain the key to identify the primary disease and secondary disease of the endodontic periodontal lesion and its management using a case series. Case description: Four cases belonging to different types of endodontic periodontal lesion such as primary endodontic with secondary periodontic lesion, primary periodontic with secondary endodontic lesion, combined lesion, iatrogenic periodontal lesion were explained. The appropriate management and its outcome for each case was elaborated and justified. Discussion: In all the four cases, patient presented with established chronic secondary disease. Hence all the cases were planned to complete the endodontic therapy initially and then proceed with periodontal therapy such as open flap debridement, hemisection and bone graft, platelet rich fibrin and guided tissue regeneration. Conclusion: Treatment outcome will be more predictable if the clinician has more thorough knowledge about the diagnosis, treatment sequence with inter-disciplinary approach .Thereby the immediate and true management of the endodontic- periodontic lesions can impede the loss of the natural tooth and delay the more complex treatment.