A DIEP flap is a type of breast reconstruction whereby deep inferior epigastric perforators (DIEP) and connected fat (and/or skin) are removed from the lower abdomen and transferred to the chest to reconstruct a breast after mastectomy without the sacrifice of any of the abdominal muscles.

The DIEP flap is similar to the TRAM flap but requires no muscle sacrifice. The perforators (i.e. blood vessels) required to keep the overlying tissue alive in the DIEP flap lay just beneath or within the abdominal muscle and must be dissected out. A preliminary CT angiogram of the inferior epigastric arteries is required for surgical planning of this dissection.