Spleen is the largest reticuloendothelial organ in the body. Receiving more than 5% of the total cardiac output, it acts as an graveyard to blood cells. It is responsible for culling (Destruction of erythrocytes) and Pitting (Removal of Erythrocytic Inclusions). In addition, it plays an important immunological role and is essential in production of IgM, Tuftsin, Properdin and Interferons. Most common indication for splenectomy in modern world is trauma which accounts for majority of cases. Several articles in literature have given a detailed view in this regard. However there is a long exhaustive list of indications for splenectomy which are described in this chapter.