Background: Few studies have focused on the clinical features of hypertrophic cardiomyopathy (HCM) with enlarged left ventricle (ELV). Hypothesis: HCM patients with ELV exhibit unique clinical features. Methods: Study participants were patients with HCM (n = 170), divided into two groups, ELV and normal sized left ventricle (NLV). Patients were also divided according to diagnosis of obstructive (n = 40), septal (n = 88), and apical (n =42) HCM. Age at diagnosis, sex, complications, electrocardiogram, symptoms, drug treatment, and echocardiographic parameters were compared among the NLV (n = 153) and ELV groups (n = 17). Results: The incidence of end-stage HCM (ES-HCM) among all HCM patients was 5.29%, and 10% in those with ELV. For all patients with HCM and those with septal HCM, there were more males with ELV than NLV. Of patients with HCM and septal HCM, left ventricular ejection fraction was significantly lower in the ELV group than the NLV group; accordingly, rates of diuretic use were higher in the ELV group than the NLV group. Among apical HCM patients, the left atrial diameter, incidence of atrial fibrillation or ST-T change, and rate of angiotensin converting enzyme inhibitor/angiotensin receptor blocker use in the ELV group were all higher than those in the NLV group. Conclusions: HCM patients with ELV are more likely to progress to ES-HCM than those with NLV. Additionally, ELV is more common in men than women and there are differences in the clinical features of different types of HCM with ELV.