The growth of microsurgical procedures has led to significant technological, scientific, and clinical advances that have made these procedures safe, reliable, reproducible, and routine in most major medical centers. In many instances, free flap reconstruction has become the primary reconstructive method for many major defects, including breast reconstruction. The advantages of free flap breast reconstruction include better flap vascularity, broader patient selection, easier insetting of the flap, and decreased donor site morbidity. Free flap breast reconstruction can occur either at the time that the mastectomy is performed or as a delayed reconstruction following a previous mastectomy. Immediate reconstructions have the advantage of avoiding scar contracture and fibrosis within the mastectomy flaps and at the recipient vessel site. The most common recipient vessel sites are the thoracodorsal vessels and the internal mammary vessels. The thoracodorsal vessels are most frequently used in immediate reconstruction because they are partially exposed during the mastectomy procedure. The internal mammary vessels are used more frequently in delayed reconstructions, to avoid repeat surgery in the axilla. This recipient site also allows more medial placement of the reconstruction. Flap selections for free autogenous breast reconstruction include the transverse rectus abdominis myocutaneous (TRAM) flap, the superior gluteal myocutaneous flap, the inferior gluteal myocutaneous flap, the lateral thigh flap, and the deep circumflex iliac soft tissue flap (Rubens). The TRAM flap is most commonly used in free flap breast reconstruction. For patients with inadequate abdominal tissue or prior abdominal surgery, the superior gluteal flap is typically used. Both the TRAM flap and the superior gluteal flap can be designed as perforator flaps, preserving all of the involved muscle and, in the TRAM perforator, all the rectus fascia. These flaps are more technically demanding, with minimal impact on donor site function. The other flaps are less frequently used and limited to special patient circumstances. Free flap autogenous breast reconstruction provides a natural, long-lasting result with a high degree of patient satisfaction. Semin. Surg. Oncol. 19:264–271, 2000. © 2000 Wiley-Liss, Inc.