One purported advantage of the free transverse rectus abdominis musculocutaneous (TRAM) flap for breast reconstruction is that, compared with the conventional TRAM flap, it has a better blood supply and therefore a lower incidence of fat necrosis. We tested this claim by reviewing the incidence of fat necrosis, both clinically and mammographically, in a group of 110 patients with 116 TRAM flap breast reconstructions who had undergone mammography of their reconstructed breasts. Of the 49 breasts reconstructed with free TRAM flaps, 4 (8.2 percent) had clinically evident fat necrosis, and 1 (2.0 percent) had fat necrosis that was detectable by mammography. Of the 67 breasts reconstructed with conventional TRAM flaps, 18 (26.9 percent) had clinically detectable fat necrosis, and 9 (13.4 percent) had fat necrosis that was detectable mammographically. Both of these differences were statistically significant (p = 0.0113 for clinical fat necrosis; p = 0.031 for mammographic fat necrosis). Fat necrosis was more common in patients who were obese or had a history of smoking, but neither association was statistically significant. We conclude that the use of the free TRAM flap reduces the incidence of fat necrosis in the reconstructed breast.