Acute respiratory distress syndrome (ARDS) is a respiratory disease characterized by a high rate of mortality. Determining the prognosis of this disease is therefore important. Lung ultrasonography has found increased use, especially in the recent years. This study aimed to score patients diagnosed with ARDS at the emergency department using point-of-care ultrasound (POCUS)-Lung and to investigate the prognosis of patients with ARDS using a scoring system. This study was designed as a single-center prospective study. The study was performed in patients admitted to the emergency department and were diagnosed with ARDS pursuant to the Berlin criteria for ARDS and who met the inclusion criteria. The patients underwent lung ultrasonography at the emergency department and were scored (A line: 0; B1 line: 1; B2 line: 2; and C line: 3 points) accordingly. The study included 100 patients with ARDS. The mortality rate was 52% in the patients in the study. The lung ultrasonography score in the mortality group (25.48 ± 3.64) was higher than that in the survivors (8.46 ± 3.61). For a cut-off value of 17.5 for the lung ultrasonography score, the sensitivity and specificity with regard to mortality indicators were 92.8% and 90.9%, respectively (the area under the curve: 0.901; 95% confidence interval: 0.945-0.985: P < .001). The findings suggested that scoring based on POCUS-Lung at the time of initial presentation at the emergency department in patients diagnosed with ARDS according to the Berlin criteria could help determine the prognosis. As POCUS-Lung proved to be an important imaging method in investigating the affected alveolar capacity, we recommend its possible use as a prognostic indicator.