The natural history of patients with well-documented presumptive diverticular hemorrhage (TICH) is unknown. Our aims are to report: 1) rebleeding rates and clinical outcomes of presumptive TICH patients with and without rebleeding, 2) conversion to definitive TICH during long-term follow-up (F/U), and 3) risk factors for presumptive TIC rebleeding. This was a retrospective cohort study of prospectively collected results of presumptive TICH patients from 1994 to 2023. Presumptive TICH was diagnosed for patients with TIC's without stigmata of recent hemorrhage and no other cause of bleeding found on anoscopy, enteroscopy, capsule endoscopy, computerized tomography angiography, or tagged red blood cell scan. Patients with ≤ 6 months of F/U were excluded. Of 139 patients with presumptive TICH, 104 were males and 35 females. Median age was 76 years. There were no significant differences in baseline demographics of rebleeders and non-rebleeders. During long-term median F/U of 73 months, 24.5% (34/139) rebled. 56% (19/34) of rebleeders were diagnosed as definitive TICH and they had significantly higher rates of readmission (p<0.001), reintervention (p<0.001), and surgery (p<0.001). During F/U, there were significantly higher rates of newly diagnosed hypertension (HTN) and/or atherosclerotic cardiovascular disease (ASCVD) in rebleeders (p = 0.033 from logistic model). All-cause mortality was 42.8%, but none was from TICH. For presumptive TICH during long-term F/U: 1) 75.5% did not rebleed and 24.5% rebled. 2) 56% of rebleeders were diagnosed as definitive TICH. 3) New development of HTN and ASCVD were risk factors for TIC rebleeding.