The gross anatomy and overall structure of the soft palate has been described in the average dog's head, however, no descriptive microanatomical studies of the dog soft palate are available, despite their possible utility in view of the manifold and important repercussions of this organ physiology. This is the first of two companion papers, dealing with the caudal part of the soft palate in the canine species, in mesaticephalic and brachycephalic dogs. Specimens from mesaticephalic healthy dogs (N = 8) were collected after euthanasia, processed for histology and sectioned at six transversal levels. Morphological stainings were used for a microscopic evaluation of the tissue layers composing the distal part of the soft palate in adult mesaticephalic dogs, and histochemical reactions were applied to assess mucin types within glandular tissue and to investigate the connective tissues. The organ was characteristically organized into a major deep musculo-connective axis mixed with salivary glands and covered by the mucosal lining on either the nasopharyngeal or the oral sides. The results of this investigation add to the general knowledge of the anatomy of soft palate in the canine species and establish baseline information for the parallel study on the long and thickened soft palate, which is typical of adult brachycephalic dogs. Anat Rec, 2011. © 2011 Wiley-Liss, Inc.