Most congenital diaphragmatic hernias are idiopathic; their cause is unknown. It is believed a combination of several factors lead to their development. Chromosomal and genetic abnormalities, environmental exposures and nutritional problems may all have a role in the formation of these hernias. It can also occur with other organ problems such as abnormal development of the heart, gastrointestinal, or genitourinary systems.

The following factors may increase your risk of an acquired diaphragmatic hernia:
blunt injuries due to a traffic accident
surgical procedures on the chest or abdomen
falls that impact the diaphragm region
stab wounds
gunshot wounds