A 5-month-old male infant was admitted with the complaints of cough & fever for 18 days and respiratory distress for 4 days. He was febrile, tachypneic (RR-58/min) with SpO2 - 94% on 2 L/min with face mask with left sided restricted chest movement with diminished breath sound. Initially he was diagnosed as left sided pleural effusion. Chest x-ray was suggestive of encysted pleural effusion (left). CT of chest revealed collapsed left lower lobe with pleural effusion and inflammatory changes in left upper lobe. Per operative finding showed pleural thickening, adhesion of oblique fissure, and perforated lower lobe of left lung. And finally infant was diagnosed as ruptured lung abscess of lower lobe of left lung with empyema thoracis. The patient was managed with decortication with segmental resection, and inj. linezolid after getting C/S and recovered.