Aims: This study’s objective was to analyze lung ultrasonography (LUS) characteristics in hospitalized pediatric patients with complicated community-acquired pneumonia (CAP). We hypothesized that LUS could be correlated with the clinical outcome in these cases.Materials and methods: In this retrospective study, we evaluated the LUS appearances (at admission and five days after the beginning of the treatment) and the progression of complicated CAP.Results: We identified 45 patients who fulfilled the inclusion criteria. Several complications occurred in these subjects during follow-up including: serofibrinous pleurisy (62.2%), empyema (15.6%), encapsulated pleurisy (11.1%), lung abscess (6.7%) and necrotizing pneumonia (2.2%). In addition, 22.2% of the patients required surgical treatment: draining tube (11.1%), decortication (6.7%) and resection (4.4%). Intensive care unit admission was needed in 8.9% of patients. The median duration of hospitalization was 14 [9.7; 19.7] days. The thickness of pleural effusion with a cut-off value of 10 mm seen by LUS was a predictor for the need for continuous thoracic drainage (p<0.01), segmentectomy or thoracoscopic surgery (p=0.03) and prolonged hospitalization over 10 days (p<0.01). Hyperechogenic pleural effusion, presence of septa and fluid bronchogram on 1st LUS evaluation were independent predictors of segmentectomy or thoracoscopic decortication (p<0.01) and of longer hospitalization (p=0.02, p<0.01, p<0.01 respectively).Conclusions: The ultrasound characteristics of complicated CAP can offer valuable information to predict the clinical evolution of CAP and so can help the development of personalized medical management plans in these patients.