Lung abscess is a rare diagnosis in the paediatric population. It most often arises as a complication of bacterial pneumonia; therefore, it is sometimes difficult to distinguish its symptoms from the symptoms of pneumonia. The abscess may be primary (it develops in immunocompetent children) or secondary (when there are favourable factors such as congenital malformations, immunological disorders, infections or neurological diseases). Treatment consists of initiating intravenous antibiotic therapy for 3–4 weeks and continuing it for 5–6 weeks orally to minimise the risk of complications. The purpose of this clinical case report was to draw the attention of general practitioners to the possible occurrence of lung abscess also in immunocompetent children. Attention was drawn to the severity of patient’s condition in the absence of auscultation symptoms. Physician’s experience has an impact on the sensitivity of the assessment of child’s clinical condition.