OBJECTIVE End-stage heart failure (HF) patients are at high risk for mortality and morbidity. We aimed to study the role of cardiac output (CO) assessed by Doppler as a noninvasive tool, to predict mortality, rehospitalization rate, and left ventricular assist device (LVAD) implantation at 6 months. RESULTS We retrospectively analyzed the data of 60 patients with end-stage HF from different etiologies and an LV ejection fraction ≤20%. Patients were divided into two groups, according to the cardiac index (CI) measured by cardiac ultrasound and Doppler - Group 1: low CO or CI <2 l/min/m2 and Group 2: preserved CO or CI ≥2 l/min/m2. Group 1 included 30 patients with mean CI of 1.52 ± l/min/m2. Group 2 included 30 patients with mean CI of 2.27 ± l/min/m2. At 6 months of follow-up, mortality was significantly higher in Group 1 compared to Group 2 (16% vs. 5%, P = 0.0001). Patients in Group 1 had higher hospitalization rate at 6 months compared to patients in Group 2 (3.5 ± 0.9 vs. 1.9 ± 0.6, P = 0.013). There was significantly more LVAD implantation in 16 patients (26%) in Group 1 versus seven patients (12%) in Group 2 (P = 0.04). CONCLUSIONS CI measured noninvasively by cardiac ultrasound is a simple and useful tool in HF patients' risk stratification and in predicting prognosis and outcome.