Hepatic nodular hyperplasia is a benign, usually clinically inapparent, proliferative lesion commonly found at necropsy in older dogs. Three examples of hepatic nodular hyperplasia are described in dogs with clinical signs compatible with hepatic disease in which ultrasonography revealed a variety of echotextural changes in the liver similar to those reported in primary or secondary hepatic neoplasia. In subsequent in vitro ultrasonographic studies of hepatic nodular hyperplasia lesions detected at necropsy in dogs without clinical signs of hepatic disease, only subtle echotextural changes were seen. Hence, hepatic nodular hyperplasia may be inapparent in vivo in many dogs. Hepatic nodular hyperplasia is a potentially confusing sporadic finding which must be considered by ultrasonographers examining dogs with clinical signs of hepatic disease. The diagnosis of hepatic neoplasia should not be made on the basis of ultrasonographic findings alone.