Background and AimWe conducted a retrospective study to identify incidence rates and potential risk factors of major adverse cardiac events (MACE) in Japanese patients with ulcerative colitis (UC), as existing data are scarce, inconsistent, and provide limited representation of the real‐world situation of MACE in Japan.MethodsWe utilized administrative claims data, collected between January 2013 and December 2022, from Medical Data Vision, Japan. Patients (aged ≥ 20 years) diagnosed with UC within ± 1 month of the prescription date during the study period were included in the incident cohort. Exclusions comprised patients diagnosed with UC in the first 365 days or with myocardial infarction, heart failure, stroke, or other ischemic heart diseases within 30 days pre‐index. The cumulative incidence rate of MACE was calculated using the Kaplan–Meier method. Multivariate Cox regression models were used to calculate hazard ratios (HRs) for all relevant potential risk factors.ResultsOf 11 407 patients in the incident cohort, 91 (0.8%) experienced incident MACE. Over 120 months, the cumulative incidence rate of MACE was 2.86% (95% confidence interval [CI]: 1.89–4.32). Significant HRs (95% CI) were found for age category (≥ 65 years) (4.557 [2.786–7.452]), diabetes (1.709 [1.030–2.835]), and atrial fibrillation (AF) (2.759 [1.188–6.405]) (all p < 0.05). Patients with a history of stroke showed numerically increased risk (1.871 [0.508–6.886]) of MACE.ConclusionsThe cumulative incidence rate of MACE was 2.86% over 120 months. Age, comorbidities of diabetes and AF, and history of stroke were the major risk factors for MACE in Japanese UC patients.