RNA was isolated from induced P3HR1 cells which synthesize Epstein-Barr virus (EBV) particles and therefore a full set of early and late antigens and from induced Raji cells which synthesize only early EBV proteins and hybridized to cloned EBV-DNA fragments spanning the entire genome. Bound mRNA was eluted and translated in vitro with rabbit reticulocyte lysate. The translation products were analyzed on SDS-polyacrylamide gels either directly or after immunoprecipitation with human sera. Most proteins could be mapped to short defined regions of the EBV genome using short restriction fragments and overlapping sheared fragments and there is evidence of splicing for some mRNA species. The synthesis of five early proteins can be seen only with hybrid-selected RNA from induced Raji cells. These mRNAs seem to be enriched in the cells restricted to early antigen synthesis.