OBJECTIVE: The objective of this study was to define and evaluate mammographic changes in patients treated with breast-conserving therapy and a new reconstructive technique that uses autologous tissue from a latissimus dorsi musculosubcutaneous flap. MATERIALS AND METHODS: Of 20 patients who underwent either immediate or delayed endoscopic latissimus dorsi muscle flap reconstruction after lumpectomy, 13 also had postsurgery mammograms available for review. Radiographic findings assessed included skin thickening, density or radiolucency at the reconstruction site, density around the flap, fat necrosis, calcifications, and the presence of surgical clips. RESULTS: Mammograms for three patients (23%) revealed thickening that we believed was attributable to radiation therapy. No patient had increased density in the flap itself; all flaps were relatively radiolucent centrally (13/13; 100%). Mammograms revealed density around the rim of the flap in four patients (31%). This density was most likely secondary to latissimus dorsi muscle fibers and did not limit radiographic evaluation. One patient had calcifications, probably secondary to fat necrosis. No oil cysts were seen. In the majority of patients (11/13; 85%), surgical clips were visible. CONCLUSION: Endoscopic latissimus dorsi muscle flap reconstruction, previously used only for mastectomy patients, is now being used for improved esthetic outcome in selected patients who desire breast conservation. Our results indicate that the mammographic findings are predictable. The most common findings are relative radiolucency centrally, with or without density from muscle fibers around the edges of the area of tissue transfer. The transplanted musculosubcutaneous flap does not interfere with mammographic evaluation.