BACKGROUND: A ten-year, single-surgeon study of 37 patients from 1993 to 2003 who underwent fat injections to improve contour deformities in their reconstructed breasts was reviewed. METHODS: Fat was harvested from elsewhere in the body using a low-pressure syringe lipoaspiration system, washed gently with saline, and injected into depressions along the margins of reconstructed breasts. Blinded physician observers judged preoperative and postoperative photographs of breasts injected with fat and categorized the degree of contour improvement as substantial, minimal to moderate, or none. Complications of fat injections were noted. A total of 43 breasts in 37 patients were injected with autologous fat during 47 discrete events; some patients had the procedure repeated and some were treated bilaterally. Of the 43 treated breasts, 25 (58 percent) were reconstructed with implants, 17 (40 percent) were reconstructed with a TRAM (transverse rectus abdominis muscle) flap, and one (2 percent) was reconstructed with a TRAM and an implant. RESULTS: There were four complications (8.5 percent) in 47 treated breasts: one breast with cellulitis that resolved with antibiotics and three breasts with small, superficial lumps--two of which were biopsied and found to be liponecrotic cysts. Patient follow-up averaged 49 weeks, ranging from 3 weeks to 6 years. There was a substantial contour improvement in ten breasts (21 percent), minimal to moderate improvement in 30 breasts (64 percent), and no improvement in 7 breasts (15 percent). CONCLUSIONS: Although fat injection in and around the reconstructed breast has limitations, such as fat necrosis and need for repeated injections, our experience indicates that overall it is a very safe technique that can improve or correct significant contour deformities that otherwise would require more complicated, riskier procedures to improve.