Introduction: Cardiac adverse events (CAEs) have become a concern as serious adverse events (AEs) of nilotinib administration. No reports have described the incidence of CAEs associated with nilotinib in Japanese patients. Thus, we conducted this study to evaluate the risk of nilotinib-induced CAEs, time to onset, incidence rates, and post hoc outcomes using the Japanese Adverse Drug Event Report database. Methods: We analysed data for the period between April 2004 and March 2022. Data on CAEs were extracted, and relative risk of AEs was estimated using the reporting odds ratio. Results: We analysed 2,021,907 reports and identified 3,545 reports of AEs caused by nilotinib. Of these, 511 reports involved CAEs. Signals were detected for 19 CAEs. Of these, electrocardiogram QT prolonged was the most frequently reported (30.9%). Fatal outcomes were observed in eight AEs: cardiac failure, atrial fibrillation, acute myocardial infarction, pericardial effusion, myocardial infarction, cardiac arrest, pericarditis, and cardiac tamponade. Of these, acute myocardial infarction, myocardial infarction, pericarditis, and cardiac tamponade exhibited mortality rates >10%. A histogram of median times to onset showed nilotinib-associated AEs occurring 3–485 days after nilotinib administration. Conclusion: We focused on CAEs caused by nilotinib as post-marketing AEs. Some cases resulted in serious outcomes. Patients should be monitored for signs of onset of these AEs not only at the start of administration but for a long period of time.