Diffuse large B cell lymphoma (DLBCL) is the most frequently diagnosed type of Non –Hodgkin’s lymphoma (NHL) in the human body and is most frequent type of NHL of oral cavity. It is an aggressive, rapidly growing neoplasm of large lymphoid cells. In the oral cavity, the majority of cases occur in the Waldeyer’s ring, followed by the buccal mucosa, tongue, floor of the mouth, and retromolar area. The representative symptoms in the oral cavity include nonspecific swelling, dental extraction wounds that do not heal, ulceration, and aposteme, and DLBCL may be misdiagnosed as osteomyelitis, periodontosis, and pyogenic granuloma, as well as malignant tumors such as squamous cell carcinoma. Here, we present a case of a 55 year old female patient who developed DLBCL in oral cavity.