Detection of diaphragmatic hernia in the acute setting is problematic and diagnosing diaphragmatic hernia as hydropneumothorax is not an uncommon mistake. We present a series of four such cases diagnosed over a 7-year period, from December 2004 to January 2011 and analyse them for how this mistake can be avoided. In case of all the patients reported by us the initial radiographs were technically compromised because the patient could not be positioned properly. Also they were examined by non-radiologists. We feel that treating surgeons in emergency department tend to overdiagnose pneumothorax as it is a life-threatening condition. We feel that in the appropriate setting suspicion of diaphragmatic hernia should be raised in patients having fractured ribs associated with homogenous opacity, which cannot be differentiated from the diaphragm. Evidence of loculation of hydropneumothorax in the appropriate setting should also raise the possibility of diaphragmatic hernia.