Isolated left ventricular noncompaction cardiomyopathy (LVNC), also known as spongy myocardium, is an extremely rare congenital disorder belonging to unclassified cardiomyopathies by the World Health Organization and classified as a genetic cardiomyopathy by the American Heart Association. Adult prevalence is 0.017-0.26% in observational echocardiographic studies. The disease occurs due to the intrauterine arrest of normal myocardial compaction, leading to left ventricular dysfunction. Reported mortality is high, ranging from 35 to 47% over a 42- to 72-month follow-up period. Knowledge regarding proper diagnosis, morbidity, and prognosis is limited; thus, this disease is subdiagnosed. Our aim is to highlight a diagnostic approach to LVNC in an elderly patient and to stress specific diagnostic signs that make the disease more recognizable. We are reporting a case of noncompaction cardiomyopathy in a 62-year-old male without any significant past medical history who was referred to our clinic for arrhythmia evaluation. The patient had several brief episodes of palpitations over the past two months. On physical examination, he presented a blowing systolic murmur at the apex and an irregularly irregular rhythm. The 12-lead electrocardiogram (ECG) demonstrated atrial fibrillation and ST-T segment depression in the V4-V6 leads. A transthoracic echocardiogram (TTE) showed signs of dilated cardiomyopathy, severe eccentric left ventricular hypertrophy, decreased contractility with an ejection fraction (EF) <30%, moderate mitral and tricuspid regurgitations, and moderate pulmonary hypertension. Multiple prominent trabeculations were noticed in the middle and apical segments of the left ventricle. The noncompacted to compacted myocardium ratio was >2.5:1. Cardiac catheterization excluded ischemic heart disease. Cardiac magnetic resonance (CMR) imaging confirmed the diagnosis of LVNC. The patient started treatment with carvedilol, ramipril, verospiron, torasemide, and rivaroxaban. An implantable cardioverter-defibrillator (ICD) was recommended. In conclusion, the diagnosis of LVNC in the adult population is often delayed because of similarities with more frequently diagnosed diseases. TTE is the initial diagnostic test of choice. Additional imaging modalities (contrast echocardiography, CMR) can help confirm the diagnosis. Early diagnosis is crucial because of the high incidence of life-threatening complications related to heart failure, thromboembolic events, and ventricular arrhythmias. Additional prospective studies are needed to improve the management and outcomes of this rare cardiomyopathy.