By immunohistochemistry, vasoactive intestinal polypeptide (VIP) was localized to nerve fibres and nerve cell bodies in the gallbladder wall of several mammals, including man. There is thus a morphological basis for accepting the powerful actions of VIP on gallbladder motility as physiological. VIP (vasoactive intestinal polypeptide), first thought of as a gut hormone, has recently been localized to a widely distributed system of nerves in the gut wall 1,2. In addition, nerves displaying VIP immunoreactivity are present in the wall of brain vessels and in the hypothalamus 1,3. Among known effects of VIP are relaxation of the gallbladder and inhibition of CCK-induced gallbladder contraction4,5. These observations prompted a search for VIP in the gallbladder wall. The present report deals with the immunohistochemical demonstration of VIP nerves in the gallbladder of several species, including man.