We describe the cloning of a novel human gene belonging to the Rh/T2/S-glycoprotein class of extracellular ribonucleases. This gene is present in a single copy in the human genome and has been mapped to 6q27, a region of the human genome prone to rearrangements associated with several human malignancies. The predicted open reading frame of the human cDNA encodes a protein of 191 amino acids, and the pattern of expression is ubiquitous. Some of the sequence features of this gene, in particular those corresponding to the bipartite RNase motif of the active site, are perfectly conserved between distant species such as human and the plant Lycopersicon esculentum. No mammalian homologues have been described so far, and this report presents for the first time both the human and the mouse sequences of the corresponding members of this class of highly conserved extracellular ribonucleases.