Actinomycosis is an infectious disease caused by Actinomyces species found as a commensal in oral flora. However, it does cause opportunistic infections with localized granulomatous and suppurative lesions intraorally once the integrity of the oral mucosal barrier is compromized and access to the underlying tissues or jaw bones is gained. The present case report highlights an unresponsive periodontal lesion associated with an actinomycotic infection in an endodontically involved tooth. The gingiva in relation to the tooth showed profuse spontaneous bleeding and suppurative discharge after multiple appointments of initial therapy which required histopathologic and microbiological assessment for diagnosis. On establishing the diagnosis of actinomycosis, treatment involved extraction of the tooth. This highlights the importance of microbiological investigations in unresponsive periodontal lesions. How to cite this article Mistry AR, Pereira R, Kini V, Padhye A, Poonja LS, Natrajan S. Management of an Unresponsive Periodontal Lesion in an Endodontic Involved Tooth Complicated by Actinomyces Species. J Contemp Dent 2014;4(3):167-172.