Effects of long-term left ventricular (LV) support on end-stage cardiomyopathy patients is unclear. We applied our LV assist system (LVAS) to six heart transplant candidates, aged 17 to 49, with dilated cardiomyopathy, including one dilated phase hypertrophied cardiomyopathy. LVAS was installed between the left atrium and the ascending aorta, and the pump was positioned parecorporeally. In all patients, their general condition improved, and their pump flows were kept at 4 to 5 L/min. Exercise was started after stabilization of their general condition under constant pump flow. Natural heart size and function were examined by echocardiography. In the beginning of assist, all patients showed impaired cardiac function and LV dilation. During LV assist, systolic function measured by ejection time improved in all patients. Left ventricular end-diastolic dimension (LVDd), showed a remarkable decrease in two patients, who were weaned from LVAS after 3 months of support. They are doing well more than 1 year and 3 years after removal; peak VO2 levels (ml/min/kg) were 30 at 1.2 years and 27 at 2.7 years after removal. In the other four patients, however, LVDd had no remarkable changes, and three could not be weaned from LVAS. The last was discontinued from LVAS after 5 months of support because of infection and died 2 months after removal. From this experience, long-term LVAS may provide the chance for recovery of the natural heart in patients with end-stage cardiomyopathy. The patients whose hearts showed remodeling were able to be weaned from LVAS, and their heart function maintained in good condition for several years.