A 1369-bp cDNA that encodes a homolog of the human transforming growth factor-beta 1 (TGF-beta 1) has been isolated from canine endothelial cells using a combination of PCR and traditional plaque-screening methods. The deduced 390-amino-acid sequence of the canine TGF-beta 1 precursor has 91-94% identity to those deduced from the previously described human and mouse TGF-beta 1 clones.