Introduction: The advantages of breast reconstruction using the DIEP flap or the muscle sparing free TRAM flap are well recognized. However, a comparative analysis between these 2 techniques has not been performed. The purpose of this study was to compare outcomes following these 2 methods of breast reconstruction as they relate to the flap and the donor site. Methods: Over the past 4 years, 177 women have had breast reconstruction using muscle-sparing flaps. This includes 89 women following use of the muscle sparing free TRAM flap of which 65 were unilateral and 24 were bilateral as well as 88 women following use of the DIEP flap of which 66 were unilateral and 22 were bilateral. The total number of flaps was 221. Muscle sparing for the free TRAM is defined as preservation of the medial and lateral segments of the rectus abdominis (MS-2). The intercostal innervation to the rectus abdominis was totally preserved in all DIEP flaps (100%) and in 92 free TRAM flaps (83%). The reconstruction was immediate for 171 (77%) and delayed for 50 (23%) flaps. Recipient vessels included the thoracodorsal for 145 flaps (66%) and the internal mammary for 76 flaps (34%). Analysis of outcomes related to flap loss, venous congestion, fat necrosis, abdominal bulge, and ability to perform sit-ups was performed. Mean follow-up was 23 months with a range of 3 to 49 months. Results: For all free TRAM flaps (n=111), outcome included fat necrosis in 8 flaps (7.2%), venous congestion in 3 flaps (2.7%), and total necrosis in 2 flaps (1.8%). An abdominal bulge occurred in 3 women (4.6%) following unilateral and 5 women (21%) following bilateral reconstruction. The ability to perform sit-ups was noted in 63 women (97%) following unilateral and 20 women (83%) following bilateral reconstruction. For all DIEP flaps (n=110), outcome included fat necrosis in 7 flaps (6.4%), venous congestion in 5 flaps (4.5%), and total necrosis in 3 flaps (2.7%). An abdominal bulge occurred in 1 woman (1.5%) following unilateral and in 1 woman (4.5%) following bilateral reconstruction. The ability to perform sit-ups was noted in all women (100%) following unilateral and in 21 women (95%) following bilateral reconstruction. Conclusion: There is no difference in fat necrosis, venous congestion and flap necrosis following DIEP or muscle sparing free TRAM flap reconstruction. The ability to perform sit-ups and the preservation of abdominal contour is increased following DIEP flap reconstruction.