Background: Literature detailing the natural history of asymptomatic penetrating aortic ulcers (PAU) is sparse and lacks long-term follow-up. This study sought to determine the rate of asymptomatic PAU growth over time and adverse events from asymptomatic PAU. Methods: A cohort of patients with asymptomatic PAU from 2005-2020 was followed. One ulcer was followed per patient. Primary endpoints were change in size over time and the composite of symptoms, radiographic progression, rupture, and intervention; cumulative incidence function estimated the incidence of the composite outcome. Ulcer size and rate of change were modeled using a linear mixed effects model. Patient and anatomic factors were evaluated as potential predictors of the outcomes. Results: There were 273 patients identified. Mean age was 75.5±9.6 years; 66.4% were male. The majority of ulcers were in the descending thoracic aorta (53.9%), followed by abdominal aorta (41.4%), and aortic arch (4.8%). Fusiform aneurysmal disease was present in 21.6% of patients at a separate location; 2.6% had an associated intramural hematoma; 23.6% had at least one other PAU. Symptoms developed in one patient who ruptured; 8 patients (2.9%) underwent an intervention for PAU (one for rupture, 2 for radiographic progression, 5 for size/growth) at a median of 3.1 years (IQR:1.0-6.5) after diagnosis. Five and 10-year cumulative incidence of the primary outcome, adjusted for competing risk of death, was 3.6% (95% CI: 1.6-6.9%) and 6.5% (95% CI: 3.1-11.4%), respectively. For 191 patients with multiple CT scans (760 total CT's) with median radiographic follow-up of 3.50 years (IQR:1.20-6.63 years), mean initial ulcer width, ulcer depth, and total diameter in millimeters (mm) was 13.6, 8.5, and 31.4, respectively. Small, but statistically significant change over time was observed for ulcer width (0.23 mm/year) and total diameter (0.24 mm/year); ulcer depth did not significantly change over time. Hypertension, hyperlipidemia, diabetes, initial ulcer width>20 mm, thrombosed PAU, and associated saccular aneurysm were associated with larger changes in ulcer size over time, however the magnitude of difference was small, ranging from 0.4-1.9 mm/year. Conclusions: Asymptomatic PAU displayed minimal growth and infrequent complications including rupture. Asymptomatic PAU may be conservatively managed with serial imaging and risk-factor modification.