The prognostic value of pulmonary hypertension (PH) estimated by echocardiography in unselected patients with acute decompensated heart failure (ADHF) is poorly studied. Between November 2014 and September 2018, 657 patients were recruited in a prospective registry of ADHF (ClinicalTrials.gov NCT02444416). The probability of pulmonary hypertension was based on European Society of Cardiology (ESC) guidelines for echocardiographic evaluation. The median survival without all-cause mortality or readmission was 7 months. During the median follow-up period of 15 months, there were 450 events including 185 deaths. In multivariate analysis, the hazard ratio (HR) of all-cause mortality or readmission for patients with a high probability of PH was 1.67 (95% CI 1.29-2.17, p < 0.001) as compared to patients with a low or intermediate probability. The left ventricular ejection fraction (LVEF) and right ventricular function (RVF) were not associated with the primary outcome-HR 1.02 (95% CI 0.81-1.29; p = 0.84) and 0.96 (95% CI 0.76-1.23; p = 0.77) respectively. In patients admitted for ADHF, a high probability of PH as evaluated by echocardiography provided the highest independent prognostic value for mortality and readmission, whereas LVEF and RVF were not associated with prognosis. The identification of patients at high risk of PH by non-invasive measurement conveys important prognostic information and may guide management.