The tear film consists of several layers: a mucin layer covering the ocular surface; an aqueous layer above that; and a lipid layer that covers the tear film surface. Mucin is important because it helps create a smooth refractive surface, decreases shear force between the corneal epithelium and aqueous layer, inhibits microbe adhesion, and prevents drying. Diquafosol is a P2Y2 purinergic receptor agonist that stimulates aqueous tear and mucin secretion from conjunctival epithelial and goblet cells respectively. In this study, Western blotting and immunohistochemical analysis demonstrated that P2Y2 receptors were present in canine conjunctivae at the level of the conjunctival epithelium and goblet cell surfaces. Following administration of 3% diquafosol to 6 laboratory dogs, there was an increase in goblet cell mucin secretion; however, this required at least 180 minutes. Diquafosol may have some use in dogs to treat corneal epithelial disorders.