Empyema necessitatis is defined as the extension of an empyema through the parietal pleura, into surrounding tissue. It is most commonly seen in adults. In this article, we report a five-year-old malnourished boy who presented with a chest wall defect due to empyema necessitatis. The mentally retarded patient was diagnosed with empyema necessitatis, hyponatremia, anemia and protein-energy malnutrition. The patient was placed in intensive care and treated for infection after establishing fluid balance and correcting deficiencies. Daily open wound dressing and debridement were performed. The chest cavity and intercostal spaces were closed with granulation tissue within two weeks. Empyema necessitates is quite rare in children. A delay in diagnosis may result in significant morbidity and mortality.