OBJECTIVE: The objective of our study was to evaluate our experience with transcatheter proximal (i.e., main) splenic artery embolization (TPSAE) in the nonsurgical management of patients with grade III-V splenic injuries, according to the American Association for the Surgery of Trauma (AAST) guidelines, and patients with splenic injuries associated with CT evidence of active contrast extravasation or blush (or cases meeting both criteria). MATERIALS AND METHODS: The records of patients with traumatic splenic injuries admitted during a 52-month period were retrospectively reviewed for patient age and sex, mechanism of injury, injury severity score (ISS), RBC transfusion requirements, AAST splenic injury CT grade, presence of active contrast extravasation or blush on CT examination, and amount of hemoperitoneum on CT examination. Demographics, CT findings, transfusion requirements, and outcome were compared using the Student's t test or chi-square test in patients undergoing standard nonoperative management and nonoperative management TPSAE-that is, TPSAE followed by nonoperative management. RESULTS: Of the 79 identified patients with splenic trauma, 67 were managed nonoperatively. Thirty-seven patients (28 men, nine women; mean age, 40 years; mean ISS, 28.8) underwent nonoperative management TPSAE and 30 patients (27 men, three women; mean age, 37 years; mean ISS, 25.1) underwent nonoperative management. Age, sex, and ISS were not significantly different between the two groups. TPSAE was always technically feasible. Splenic injuries were significantly more severe in the nonoperative management TPSAE group than in the nonoperative management group with respect to the mean splenic injury AAST CT grade (3.7 vs 2, respectively; p < 0.0001), active contrast extravasation or blush (38% [14/37] vs 3% [1/30], respectively; p = 0.0005), and hemoperitoneum grade (1.6 vs 0.8, respectively; p = 0.0006). Secondary splenectomy rate was lower in the nonoperative management TPSAE group (2.7% [1/37] vs 10% [3/30]). No procedure-related complications were encountered during early and delayed clinical follow-up. CONCLUSION: TPSAE is a feasible and safe adjunct to observation in the nonoperative management of severe traumatic splenic injuries. The secondary splenectomy rate using nonoperative management TPSAE (2.7%) is among the lowest reported despite a selection of severe injuries.