The diagnosis of delayed rupture of the spleen is demonstrated and discussed by presenting a case in which the patient had significant thoracoabdominal trauma with an initially normal liver/spleen scintigram and benign hospital course. Twenty-three days after the trauma, the patient developed an acute abdominal crisis that brought him to the emergency room where an emergency ultrasound revealed hemoperitoneum and a subcapsular hematoma. At laparotomy, a splenic rupture was found. A splenectomy was not performed. Postoperative liver/spleen scintigram showed a persistent defect which was not present on the initial liver/spleen scintigram.