This paper reports a 74 year-old-man with a hypertrophic cardiomyopathy associated with mid-ventricular obstruction and a secundum type atrial septal defect. He had been suffering from shortness of breath and occasional attacks of dizziness. Doppler echocardiography revealed the gradient in the mid-left ventricular area. A transesophageal echocardiogram confirmed the findings of transthoracic study and an ostium secundum-type atrial septal defect was documented. The present case represents a rare combination of hypertrophic cardiomyopathy associated with midventricular obstruction, and an ostium secundum type atrial septal defect in an elderly man.