A virion-like particle (VLP) was isolated from the culture fluid of P3HR-I cells. VLPs were separable from the enveloped Epstein-Barr virus (EBV) through rate-velocity sedimentation by virtue of their greater density. VLPs comprised electron-dense nucleoid material and the surrounding round or oval envelope which ranged from 100 to 150 nm in diameter. The polypeptide constitution of VLPs was very similar to that of enveloped EBV by SDS-polyacrylamide gel electrophoresis. VLPs contained reasonably specific cellular DNA (VLP DNA) with a sedimentation coefficient of 48S, which was cleaved into 5, 8, and at least 30 specific DNA fragments by digestion with BamHI, SalI, and EcoRI, respectively. Blot hybridization data suggested a limited heterogeneous genomic organization of VLP DNA and the presence of a VLP DNA-related molecule(s) in human cord lymphocytes.