To evaluate the left ventricular function and determine etiology of left ventricular thrombus in 26 cases. Prospective observational study. Medical Unit of Ayub Teaching Hospital, Ayub Medical College, Abbottabad. Patients with left ventricular thrombi diagnosed with echocardiography from May 1999 to June 2001 were studied for its etiology and left ventricular function. Fifty-six percent of left ventricular thrombus cases were due to chronic ischemic heart disease while 36% had dilated cardiomyopathy. Left ventricular aneurysm was seen in 7.8% cases. Mean age was 54±3 years with 74% males and 26% females. Mean ejection fraction was 22 ± 2.5% in dilated cardiomyopathy cases while it was 35 ± 17% in cases with underlying coronary artery disease. Chronic ischemic heart disease and dilated cardiomyopathy are the main causes associated with left ventricular thrombi. Impaired left ventricular function is a common denominator in these cases.