Iatrogenic diaphragmatic entry following thoracic surgery is rare with only two cases reported till date. This case reports on a 46-year-old male with persistent pleural sepsis due to right empyema thoracis despite best medical ef- forts. Following a right thoracotomy and decortication, the right diaphragm was inadvertently incised due to dense adhesions between the diaphragm and thickened cortex. To our knowledge, this is the third case reported of iatro- genic diaphragmatic entry following thoracic surgery for empyema thoracis. The pearls from this case report is that any evidence of empyema thoracis involving the lower lobe on imaging should warn the surgeons to be aware of inadvertent entry into the peritoneal cavity, as the diaphragm can be adherent to the cortex trapping the lower lobe.