Aedes albopictus cells infected with vesicular stomatitis virus (VSV) and maintained in medium lacking methionine produced 1000-fold less infectious virus than cultures maintained in complete medium. Analysis of viral macromolecular synthesis in cells maintained in the presence of varying concentrations of methionine showed that the reduction in virus yield was directly correlated with a reduction in viral RNA and protein synthesis. Of the viral mRNA which was made in methionine-starved cells the majority was not polysome associated. In contrast, virtually all of the virus mRNA in cells maintained in complete medium was polysome associated. In vitro translation of those mRNAs from methionine-starved cells, which were not polysome associated, indicated that they could be translated in vitro as efficiently as polysome-associated virus mRNA but only if the methylation inhibitor, S-adenosylhomocysteine, was not present. These results strongly suggest that methionine starvation of A. albopictus cells inhibits VSV replication by preventing cap methylation of the viral mRNAs, and thus reducing the efficiency with which they are translanted.