Background: Damage control surgery and management of the open abdomen has led to a significant improvement in survival in trauma and emergency surgical patients. However, subsequent abdominal reconstruction has become a significant challenge. The objective of this study was to compare 2 different acellular dermal matrices in regard to hernia recurrence and complications in patients who present with a large complicated ventral hernia as a result of trauma or emergency surgery. Study Design: A prospective quasi-experimental time-interrupted series design was used to evaluate the incidence of hernia recurrence in trauma/emergency surgery patients who had a ventral hernia repair with a biologic matrix. From January 2005 to December 2007, 55 patients with a complicated ventral hernia were repaired with AlloDerm (Life Cell Corporation). Beginning in February 2008 to January 2010, 40 patients with the same criteria were repaired with FlexHD (Musculoskeletal Transplant Foundation) and followed prospectively over the following year. The primary outcome for this study was hernia recurrence (functional or real) at 1 year. Other outcomes variables included abdominal laxity, seroma formation, and wound or intra-abdominal infection. Results: There was no significant difference in age, sex, and body mass index between the groups. In addition, there was no significant difference in the mean hernia size and size of the acellular dermis that was inserted. At 1 year postsurgery, all of the AlloDerm patients were diagnosed with recurrence requiring a second formal repair. Eleven patients (31%) whose hernias were repaired with FlexHD were diagnosed with a recurrence requiring a second formal repair. Conclusions: FlexHD appears to have reduced the recurrence and laxity rates while maintaining a similar complication profile compared with AlloDerm in trauma/emergency surgery patients with large complicated ventral hernias.