Primary Effusion Lymphoma (PEL) is an infrequent subtype of Non-Hodgkin`s Lymphoma which is characterized by lymphomatous effusions in body cavities, not-associated with mass lesions. Generally PEL is reported in immunocompromised patients infected with human immunodeficiency virus (HIV) and Human Herpes Virus-8 (HHV-8). Recently HIV and HHV-8 negative cases were also reported. Here, we report a 76 year-old man with HIV and HHV-8 negative PEL successfully treated with R-COP chemotherapy protocol.