Endo –perio lesions are the lesions affecting both the pulp and the periodontium individually or combined in the same tooth. They are interrelated by various pathways like apical foramen, lateral canals, dentinal tubules which can result into the spread of disease from one tissue to another and have differing pathogenesis, making it necessary for the clinicians to have a complete understanding about the disease process for the successful diagnosis and treatment of the involved lesions. The aim was to evaluate the bacterial profile in endodontic– periodontal lesions and to assess antibiotic susceptibility to the four antibiotics namely Augmentin, Doxycycline, Ofloxacin+ornidazole, Cefotaxime.