We describe the case of a 8 year-old child with acute respiratory distress syndrome (ARDS) during H1N1 swine flu. Lung ultrasound performed at the time of admission showed a typical ARDS ultrasound pattern, with multiple sonographic signs of interstitial oedema (also known as B-lines or ultrasound lung comets), and diffuse bilateral sub-pleural lung consolidations. After five days of anti-viral therapy, lung ultrasound showed a reduction of the dimension of consolidations, not clearly visible at chest X-ray, helping in the management of the patient.