CONCLUSIONS Patients with significant loss of abdominal wall soft tissue represent a reconstructive challenge. The purpose of this study was to describe the authors' experience using microvascular free tissue transfer to repair complex abdominal wall defects with insufficient overlying soft tissue. In this report, the authors highlight their techniques and experiences in performing microvascular free tissue transfer to the abdominal wall for these massive, complex defects. In total, 14 patients who underwent 16 free-flap reconstructions were included in the series. The patients' mean age was 50 ± 14 years, and mean body mass index was 27 ± 5 kg/m2. The mean hernia defect size was 412 ± 149 cm2. Ten flaps were fasciocutaneous anterolateral thigh flaps, one myocutaneous anterolateral thigh flap, two subtotal thigh flaps, one myocutaneous latissimus dorsi flap, one parascapular/latissimus dorsi flap, and one free filet of the lower leg. Five cases (36 percent) developed hernia recurrence, and seven developed surgical site complications. All flaps survived, with no total flap loss. This report highlights that microsurgical free tissue transfer in combination with mesh repair is a safe and reliable method for restoring complex, large, full-thickness abdominal wall defects. This case series illustrates a number of techniques and considerations that are of importance to achieve a favorable outcome when faced with these complex defects. METHODS Therapeutic, IV.