Objective Splanchnic artery aneurysms (SAAs) are uncommon, and standards for surveillance and intervention are lacking. The goal of this study was to review our 20-year experience with managing SAAs. Methods The Research Patient Data Registry at the Massachusetts General Hospital was queried, and all patients with SAAs identified by axial imaging from 1994 to 2014 were included. Aneurysms were stratified into two cohorts: those that underwent early intervention (<6 months after lesion discovery) and those that received surveillance. Primary study end points included aneurysm growth or rupture during surveillance and patient 30-day morbidity or mortality after aneurysm repair. Results There were 264 SAAs identified in 250 patients. In 166 patients, 176 SAAs (66.6%) were placed into the surveillance cohort; 38 SAAs (21.6%) did not have subsequent axial imaging and were considered lost to follow-up. Mean aneurysm size in the surveillance cohort at first imaging study was 16.28 mm (8-41 mm), and mean surveillance time was 36.1 months (2-155 months); 126 SAAs (91.3%) remained stable in size over time, and 8 SAAs (5.8%) required intervention for aneurysm growth after a mean of 24 months. There were no ruptures in the surveillance cohort. There were 88 SAAs (33.3%) repaired early. Mean size of SAAs that were repaired early was 31.1 mm (10-140 mm). For intact SAAs, 30-day morbidity and mortality rates after repair were 13% and 3%, respectively. In the early repair cohort, 13 SAAs (14.7%) were ruptured at presentation. The 30-day morbidity and mortality rates after rupture were 54% and 8%, respectively. Five ruptured SAAs (38%) were anatomically located in the pancreaticoduodenal arcade. On univariate analysis, pancreaticoduodenal aneurysms were strongly associated with rupture (P =.0002). Conclusions Small SAAs (≤25 mm) are not prone to significant expansion and do not require frequent surveillance imaging. Imaging every 3 years for small SAAs is adequate. Aneurysms of the pancreaticoduodenal arcade and gastroduodenal aneurysms are more likely to rupture and therefore warrant a more aggressive interventional approach.