The nature of the refractoriness of C6 rat glioma cells to herpes simplex virus type 2 (HSV-2) was examined. Infection of C6 cells with HSV-2 results in low virus yields, not exceeding the input virus. Although virus growth studies suggested a restricted cycle of virus replication, synthesis of HSV-2 DNA and HSV-2-specific antigens could not be detected. In addition, HSV-2 yields in C6 cells were unaffected by interferon, cycloheximide, tunicamycin, actinomycin D and cytosine arabinoside. However, trypsin, but not EDTA, treatment of infected C6 cells at 4 hours postinfection (p.i.) reduced maximal HSV-2 yields at 24 hours p.i. by 61 percent. These data: 1) indicate that HSV-2 fails to replicate in C6 cells and is prohibited from directing the synthesis of virus macromolecules; and 2) suggests that the increment of HSV-2 yields observed during the synthesis phase of the virus growth cycle represents re-envelopment and egress of a portion of the input virus.