C-type natriuretic peptide is a 22-amino acid peptide that was initially identified in the central nervous system. The distribution of C-type natriuretic peptide, which has structural homology with atrial and brain natriuretic peptides, is wide and includes the endothelium, myocardium, gastrointestinal, and genitourinary tracts. The biological effects of this peptide are being elucidated in a number of sites in a number of species; however, the novel endothelial site of production of C-type natriuretic peptide and the proximal situation of its receptor in vascular smooth muscle suggest that this vascular natriuretic peptide system may play a role in concert with other local systems in the control of vascular tone.