Monkey kidney cells infected with the J 670/71 strain of acute hemorrhagic conjunctivitis (AHC) virus in the presence of actinomycin D synthesized two species of viral RNA. One species had properties similar to the virion RNA, sedimented in a sucrose gradient with a sedimentation coefficient of 34S, and was sensitive to RNase. The other species sedimented at 18S and was resistant to RNase. The inability of AHC virus to replicate at 39 degrees was attributed to a lack of virus-specific RNA synthesis in infected cells.