Idiopathic atraumatic splenic rupture (ASR) is rare, especially in neonates and can result in the spontaneous hemorrhage of the organ, abdominal distension, and hemoperitoneum. This condition can be fatal without prompt diagnosis and surgical intervention. The pathophysiology of ASR is difficult to understand due to its rarity; however, retrospective reviews have found an association with neoplasm, infection, inflammatory diseases, and anticoagulant drugs. Therefore, it is essential to report this rare occurrence. This case report involves a 2-day-old neonate born to a mother with chronic hypertension, chorioamnionitis, and a carrier of cystic fibrosis. An abdominal sonogram followed by contrast-enhanced computed tomography (CT) revealed hemoperitoneum with possible active bleeding and lack of definite visualization of the spleen. During emergency laparotomy, the attempt to preserve the organ was unsuccessful, requiring splenectomy. The neonate recovered well from the procedure and was discharged on the 18th day of life.