The abdominal wall function of 57 patients who have undergone TRAM flap breast reconstructions using the whole rectus muscle, on one side (33 patients) or both (24 patients), was evaluated 6 months to 2 years after surgery. The defect was repaired with a Teflon mesh buried in the rectus sheath. There was a perfect tolerance to the mesh, and no hernia or bulging of the abdominal wall developed. Patients had less back pain after (10 patients) than before (18 patients) the operation and found their sit-up and sport possibilities about the same as before. Detailed assessment of the abdominal muscles by the physiotherapist showed, however, a decreased function, more evident in bilateral cases. CT scans demonstrated a medialization of the lateral muscles, leaving only a small medial portion of the abdominal wall devoid of muscles. On the whole, no problem of clinical significance was encountered, and patients showed a high degree of satisfaction with the operation.