Left ventricular (LV) pseudoaneurysms are rare and life-threatening conditions caused by myocardial rupture contained by external tissues. Idiopathic cases, with no identifiable cause, are exceptionally rare. We report the case of a 45-year-old asymptomatic male with no significant medical or family history, in whom an incidental LV pseudoaneurysm was discovered during a routine health check. Imaging revealed a 30×29×21 mm pseudoaneurysm with thin walls and active blood flow, posing a high risk of rupture despite the absence of symptoms. Preventive surgical repair was performed using a bovine pericardial patch reinforced with sutures, Teflon felt strips, and surgical glue. Postoperative recovery was uneventful, and follow-up imaging confirmed successful repair with no recurrence. This case highlights the rarity of idiopathic LV pseudoaneurysms and the importance of early diagnosis and intervention to prevent fatal outcomes.