Human herpes virus-8 (HHV-8)-associated primary effusion lymphoma (PEL) is an unusual lymphoma confined to the body cavities, which primarily affects human immunodeficiency virus (HIV)-positive men at high risk for Kaposi's sarcoma (KS). We describe two HIV-negative elderly Italian men, who developed pleural HHV-8-positive PEL in association with other diseases (systemic hypertension, colonic carcinoma, chronic obstructive airways disease, dilated cardiomyopathy), but without KS. Thoracic computed tomography revealed unilateral pleural effusion and pleural thickening. Thoracentesis disclosed large lymphoma cells, with no T- or B-cell associated antigens, clonal rearrangement of the immunoglobulin heavy chain gene and the presence of HHV-8 but not Epstein-Barr virus deoxyribonucleic acid sequences. Our cases differ from most pleural effusion lymphomas, in that they are non-acquired immunodeficiency syndrome-related. This highlights the possible human herpes virus-8-associated primary effusion lymphoma risk among elderly human immunodeficiency virus-negative patients, particularly Italians, in whom human herpes virus-8 seroprevalence rates and incidence of classic Kaposi's sarcoma are high.