Primary effusion lymphoma (PEL), formerly known as body cavity-based lymphoma, is a high-grade B-cell non-Hodgkin's lymphoma associated with Kaposi's sarcoma and human herpesvirus 8 infection. It usually affects serous body cavities and results in recurrent lymphomatous effusions. PEL is often diagnosed in patients with HIV infection and carries a poor prognosis, with median survival near 6 months. We describe a patient who presented with symptomatic pericardial effusion, secondary to newly diagnosed PEL, and no prior history of HIV infection.