Objective: Compare the success of non-operative treatment of blunt splenic injury grades III and IV, before and after the introduction of angioembolization. Methods: Data collected from electronic medical reports of patients presenting blunt splenic injury (BSI) grades III and IV (subcapsular hematoma was not included), according to AAST (American Association for Surgery of Trauma) classification and undergoing nonoperative management at Hospital João XXII from January 2014 to July 2017. Data was compared to a case series of these nonoperative injuries from November 2004 to December 2013 at the same institution, when angioembolization was not used. The study level of significance was 5% and outcome was failure of non-operative treatment. Analyses were made using the software R3.6.3 and MINITAB version 14. Results: From November/2004 to December/2013, 389 patients undergoing conservative treatment were studied, 332 (82,8%) of which presented with blunt splenic injury grade III and 67 (17,2%) had lesions grade IV, treatment failure (need for splenectomy) occurred in 36 (11%) patients with injury grade III and 22 (33%) with grade IV. From January/2014 to July/2017, when angioembolization was available, 195 patients underwent conservative treatment, 110 (56,4%) with blunt splenic injury grade III and 85 (43,6%) with grade IV. In this group, treatment failed in 4 (3,6%) with injury grade III and 6 (7%) grade IV. Conclusion: Nonoperative management of blunt splenic trauma associated with angioembolization is associated with a reduction in splenectomy in splenic injuries grades III and IV.