The purpose of this experiment was to study the histologic changes of submabdibular glands of which ducts were cut and ligated. In A-Group of 4 dogs, the right submandibular ducts were intact as control, and ducts were ligated and the left submandibular ducts were cut. The submandibular glands were studied histologically after 2, 5, 8, and 12 weeks. The results were as follows : 1. The submandibular glands of which ducts were found as normal as control submand ibular glands. 2. The submandibular glands of which ducts were ligated were atrophied. 3. The cut submandibular ducts did not cause histologically atrophic changes on submandibular glands until 12 weeks.