When the free TRAM flap was introduced for breast reconstruction, it was supposed to have many advantages over the pedicled TRAM flap: good perfusion of all four zones, better mobility and easier shaping of the breast, lower incidence of abdominal-wall complications, and less restrictive selection of patients. However, we have experienced several complications after free TRAM flaps in our practice, including fat necrosis, partial and complete flap necrosis, abdominal-wall weakness, and hernias. In order to evaluate the incidence and types of complications, as well as the influence of preoperative risk factors (chemotherapy, radiotherapy, overweight, smoking habits, and abdominal scars), on complications, a multicentric prospective study including Bern (Switzerland), Leuven (Belgium), Stuttgart (Germany), and Verona (Italy) was designed. In 111 consecutive patients, operated on over a period of 18 months, 123 flaps were done; 99 flaps were unilateral and 24 bilateral, and 36 were used for primary and 87 for late reconstruction. There was no preoperative selection of patients. The follow-up period was from 8 to 24 months (average 19 months). A two-team operating approach was used. All four zones were always included in the flap, and the end-to-end anastomoses were done to the thoracodorsal, the circumflex scapular, or the internal mammary arteries. The total number of fat and flap necroses was 24 (19.5 percent), 6 (5 percent) minor and 4 (3 percent) major fat necroses, 2 (1.6 percent) minor and 6 (5 percent) major flap necroses, and 6 (5 percent) total flap necroses. Twenty-two (20 percent) patients had abdominal-wall complications. The results of this study show that the complication rate of free TRAM flaps is considerable. Preoperative risk factors did not play a major role in the development of complications and should not be considered as contraindications for free TRAM flap surgery. All total flap failures resulted from impaired arterial inflow to the flap, and the choice of recipient vessel did not influence the outcome. The incidence of total flap failures might be reduced by good postoperative flap monitoring and early revision of the anastomosis. Partial fat and flap necroses might be prevented by removing the fat under the scarpa fascia in zones 4 and 3 or by reducing zone 4. Sparingly harvesting the rectus muscle and its sheath as well as the use of mesh in the rectus sheath repair may reduce the abdominal-wall complications.