Over the last five past years, three patients required urgent operation in our institution for hemorrhagic shock after rupture of a post-traumatic splenic artery aneurysm. Those patients had undergone non- operative management (NOM) of grade III, IV (AAST classification) splenic injury 9, 13, and 22 months earlier. Two of them had a CT scan 30 days after initial trauma with no evidence of a developing splenic artery aneurysm. All three patients survived after proximal ligature of splenic artery and hemostatic splenectomy. Our experience with these three cases suggests that a delayed follow-up for patients at high risk is indicated in order to prevent this dramatic complication by early intervention. The modality of this follow-up should be determined by a prospective multicenter study.