Introduction Chest Ultrasound can help in rapid treatment of acute respiratory failure in intensive care units when rapid decisions are needed and especially when patients' transport is a big difficult. Therefore, CUS can be considered an attractive complementary diagnostic tool and one of the most promising techniques for differentiation and  management of critically ill patient with either acute cardiogenic pulmonary edema (APE) or acute respiratory distress syndrome (ARDS). Aim :This study  was aim to clarify the role of chest ultrasonography to differentiate between ARDS(Acute respiratory distress syndrome) and  Acute cardiogenic pulmonary edema  in patients admitted to ICU with acute dyspnea.  Patients and methods  Lung US was applied to respiratory distressed patients  In Benha  University Hospital ICUs on 60  patients who divided into  APE group (23 cases) or ARDS group (37 cases). LUS examination focused on detecting  the following pleuropulmonary signs in both groups: alveolar–interstitial syndrome(AIS),  absent or reduced lung sliding,spared areas ,subpleural consolidation pleural line abnormalities, and pleural effusion. Result Alveolointerstitial syndrome (AIS )was observed  in 100% of  APE patients and in100% ofARDS patients . Absent or reduced lung sliding was observed in 0% of  APE patients  and in 97.3% of ARDS patients(P=0.001). spared areas  were found in 0% of APE patients and100% in ARDS patients(=0.001),lungConsolidations were present in 4.3% of APE patients in 94.6% of ARDS patients with (P=0.001). Pleural line abnormalities were observed in 13% of APE patients and in 100% of  ARDS patients(P=0.001),and Pleural effusion was present in 100% Of APE patients and in 40.5% of  ARDS patients with APE (P=0.001).  All these signs, except the AIS sign,presented a statistically significant difference in differentiation  between ARDS and APE, resulting in specific  ultrasonographic pleuropulmonary signs of ARDS and APE. Conclusion Results of the current study demonastrated that  LUS play asignificant role in management of respiratory failure patients especially cases of  ARDS and  APE in ICU by helping in rapid diagnosis and differentiation between both types in accompanying with EChocardiodraohy and IVC diameter measurement. Absence of reduced lung sliding,spared areas,suppleural consolidation, pleural line abnormalities, on a background of AIS  considered specific  features for differentiation between ARDS and APE.