Background: over the past 15 to 20 years, lung ultrasound has developed as an important modality for the bedside diagnosis of pneumonia both in the Emergency department and intensive care unit (ICU) settings, Platelets play a crucial role in antimicrobial host defenses and the coagulate system, it is hypothesized that an abnormal platelet count may be an important marker to assess severity of disease in patients with community acquired pneumonia (CAP). Aim of the Work: the aim of this study was to evaluate the role of chest ultrasound and blood platelet in diagnosis and assessment the severity of community acquired pneumonia. Patients and Methods: this was a prospective study carried out at Chest Department and Respiratory ICU at El-Hussein University hospital in the period from September 2017 to June 2018. The study included 50 cases of CAP; 29 cases male and 21 cases female with mean age (48.32+15.62 years) admitted at the Chest Department and Respiratory ICU were enrolled in this study after obtaining informed consent. Results: the results of this study revealed that the transthoracic ultrasound can easily detect signs of consolidation and assess the success of pneumonia correlation with CURB 65 SCOR and blood platelet. Conclusion: thoracic ultrasound is a simple, bedside test used for diagnosis of pneumonia can differentiate between simple pneumonia and post stenotic pneumonia, atelectasis and mass. However, it is operator dependent and needs training.