The spleen is the largest organ of the lymphatic system in the human body. It is located intraperitoneally in the upper left quadrant. Its length changes depending on the age of the child, reaching its maximum length at the age of 14. The main functions are hematopoiesis, immunological function, depot function, metabolic function, and filtration of blood cells. Pathological conditions are divided into diseases (congenital or acquired) and injuries. Congenital diseases are asplenia, polysplenia, accessory spleen and wandering spleen, while acquired diseases are benign diseases (hereditary spherocytosis, hemoglobinopathies and idiopathic thrombocytopenic purpura), malignant diseases (lymphomas and leukemias), benign or malignant tumors, cysts or infections. The main possible injury of the spleen is a rupture caused by trauma, iatrogenic or accidental, with the spleen being the most frequently injured intra-abdominal organ in blunt trauma (mainly traffic accidents). Possible methods of treatment for diseases and injuries of the spleen are conservative and surgical. Conservative treatment includes rest, fluid replacement, blood transfusion and regular controls. In splenectomy, which is a surgical method, the spleen is removed. It can be total, partial, and subtotal; open or laparoscopic. Due to the immunological importance of the spleen in children, a sparing method should be chosen to preserve as much of the parenchyma as possible, unless the child is life-threatening or there is no other solution but to perform a total splenectomy. Regardless of the procedure, early complications like bleeding, thromboembolism, pulmonary complications, infectious complications, complications of intraoperative adjacent organs and late complications like post-splenectomy sepsis can occur. Due to the mentioned complications, perioperative care is extremely important. It includes vaccine, antibiotic and thromboprophylaxis.