Clinically, it is true that gastric ulcer is more common along the lesser curvature and less common along the greater curvature. To elucidate this difference in ulcerognesis, two experimental ulcers were prepared in dogs at the sites, one at the angular incisure and the other at the corresponding greater curvature after the method by Hatafuku & Thal. The fates of these ulcers studied endoscopically, macroscopically, histologically and with the use of microangiography. The results obtained are summarized as follows. 1) When two ulcers only were prepared, better healing was consistent for the greater curve ulcer. 2) Experimental ulcers with simultaneous ligation of gastric vessels resulted in poor healing of both ulcers, though the greater curve ulcer showed better healing than the lesser curve ulcer. 3) Endoscopically, dogs with vessel ligation showed antral congestion and edema. These findings, however, disappeared in 3 to 4 weeks. 4) Histamine injection accelerated the rate of early perforation and both experimental ulcers showed no tendency of healing. In conclusion, delayed healing was almost consistent for the lesser curve ulcer under various conditions. The cause for this may be explained by the increased motility with repeated ischemic condition at the lesser curvature.