Human herpesvirus 8 (HHV-8), a gammaherpesvirus implicated in Kaposi's sarcoma, primary effusion lymphoma, and Castleman's disease, encodes several pathogenically important cellular homologs. To define the HHV-8 transcription program, RNA obtained from latently infected body cavity-based lymphoma 1 cells induced to undergo lytic replication was used to query a custom HHV-8 DNA microarray containing nearly every known viral open reading frame. The patterns of viral gene expression offer insights into the replication and pathogenic strategies of HHV-8.