Citrus psorosis virus (CPsV) causes a citrus disease occurring worldwide. Isolate CPV 4 has a genome with three single-stranded RNAs. The complete sequence of RNA 2 (1643 nucleotides) is reported here. Northern blot hybridization with strand-specific probes showed that most of the encapsidated RNA 2 is of negative polarity, although a small amount of the complementary strand may also be present in particles. The RNA 2 complementary strand contained a single open reading frame encoding a protein of 476 amino acids, which includes a motif resembling a nuclear localization signal. The sequence of this putative protein shows no significant similarity to any other in the databases. In the 3'-terminal untranslated region there is a putative polyadenylation signal. No subgenomic RNAs derived from RNA 2 were detected.