Certain strains of Leishmania guyanensis carry persistently infecting double-stranded RNA viruses. The viral polymerase has been shown to have both transcriptase and replicase activity. To date, only full-length RNA transcription of minus and plus strands have been reported. This report describes the synthesis of a 320 nt transcript which is complementary to the 3' end of the minus strand RNA. This plus-stranded short transcript was first detected in an in vitro polymerase assay. It was also detected in virus-infected Leishmania cells by a reverse transcription-polymerase chain reaction assay and by Northern analysis of infected Leishmania cell RNA.