Postsplenectomy complications have stimulated surgeons to opt for partial splenectomy as a more desirable technique for several diseases and in some cases for trauma to the spleen. 2. We studied spleen viability in 15 dogs submitted to subtotal splenectomy while maintaining the upper pole and upper splenogastric vessels. Macro- and microscopic histological studies as well as Tc99m-labeled heat-damaged erythrocyte scintigraphic analysis of splenic blood irrigation were carried out. 3. We conclude that: a) the splenogastric vessels are sufficient for the maintenance of spleen irrigation and drainage; b) the spleen remnants develop increased cellularity of the splenic cords and lymphoid folliculi; c) the length of the spleen remnants does not change for at least 2 months after surgery.