Background & Aims Diverticular disease and cardiovascular disease share several risk factors. Inflammation associated with diverticular disease could predispose to cardiovascular disease. We assessed the association between a diagnosis of diverticular disease and subsequent arterial and venous thromboembolic events, adjusting for related comorbidities to explore a possible causal relationship. Methods We identified 77,065 incident cases of diverticular disease from 1980–2011 from Danish nationwide medical registries; these were matched for age and sex with 302,572 population comparison cohort members. Individuals with a history of cardiovascular disease were excluded. We used Cox proportional hazards regression to compute incidence rate ratios, comparing the incidence of acute myocardial infarction, stroke, venous thromboembolism, and subarachnoid hemorrhage in patients with diverticular disease with those of the population cohort members, adjusting for age, sex, obesity, diabetes, hyperlipidemia, chronic obstructive pulmonary disease, connective tissue disease, renal disease, and treatments and medications. Results The adjusted incidence rate ratios for patients with diverticular disease, compared with population cohort members, were 1.11 (95% confidence interval [CI], 1.07–1.14) for acute myocardial infarction, 1.11 (95% CI, 1.08–1.15) for overall stroke, 1.36 (95% CI, 1.30–1.43) for overall venous thromboembolism, and 1.27 (95% CI, 1.09–1.48) for subarachnoid hemorrhage. The relative risk of each event remained increased after we adjusted for changes in aspirin use or for endoscopy or colorectal surgery after the diagnosis of diverticular disease. These findings also held after excluding the first year of follow-up and limiting the analysis to patients with diverticulitis. Conclusions On the basis of an analysis of Danish medical registries, a diagnosis of diverticular disease is associated with a modest increase in risk of arterial and venous thromboembolic events after adjustment for related disorders.