Methods: cross sectional descriptive study combined prospectively on 149 patients from 3 months to 15 years old were diagnosed by respiratory specialists as pneumonia based on clinical symptoms, x-rays admission at Nhi dong 1 Hospital from 7/2014 to 5/2015. Results: Ultrasound detected 96% of the number of cases of pneumonia and had high value in detecting pleural effusion (100%), lung abscesses (66.7%).