Ventral hernias occur following 11-23% of laparotomy (abdominal wall) incisions. With 5 million laparotomies performed annually in the United States, there are an estimated 400,000 ventral hernia repairs each year, making it one of the most common procedures performed by general surgeons and adding over 8 billion dollars to US healthcare costs. A synthetic prosthetic mesh repair during a clean case (in which there is no bacterial contamination) is the standard of care, yielding the best long-term results and reducing the hernia recurrence rate by 50%. However, the management of ventral hernias in the setting of bacterial contamination remains a major clinical challenge since placing a synthetic prosthetic into a contaminated field is generally thought to result in an unacceptably high rate of complications, including surgical site infection, enterocutaneous fistula and recurrent hernia formation. Therefore, until the recent introduction of biologic prosthetics, the standard of care fr repairing a ventral hernia in the setting of a contaminated wound was a two-stage procedure. While the two-stage procedure is thought to reduce the risks of infection-related complications by avoiding placement of synthetic prosthetic material into a contaminated wound, it unfortunately requires the patient to undergo two separate operations, hospitalizations, and recovery periods, during which time they often are unable to work and must endure a limited level of physical activity. Several biomedical companies have recently introduced new biologic prosthetics to address the clinical challenge of treating complex ventral hernias in a manner that avoids the two-stage repair. Since biologic prosthetics are derived from living tissue, these products are promoted as resisting infection and enabling wound healing in contaminated surgical fields. Currently, an intriguing variety of biologic prosthetics, derived from collagen-rih porcine, bovine or human tissues such as skin, intestinal submucosa or pericardium, are available for the one-stage repair of complex ventral hernias. However, these products are very expensive and long-term outcome data is unavailable. In fact, data are accumulating that question the overall clinical efficacy of such products, despite their intuitive appeal as more natural tissue replacements. Simultaneously, there is increasing data indicating that permanent synthetic prosthetics like polypropylene (Prolene), which is inexpensive and has been in clinical use for over fifty years, can be safely used in contaminated surgical fields. Yet, these studies are small, retrospective, non-randomized and ultimately inconclusive. Experts agree that prospective randomized clinical studies comparing the safety and efficacy of biologic versus permanent synthetic prosthetics for repair of complex ventral hernias are needed to confidently guide surgical decision- making. This study will compare the efficacy, safety and cost of a permanent, synthetic prosthetic versus a biologic prosthetic for the one-stage repair of ventral hernias in the setting of wound contamination. Since currently available data are inadequate to confidently guide clinical decision making, surgeons are presently forced to rely on a combination of personal experience, preclinical data, industry marketing, and clinical intuition when faced with these challenging patients. Thus, in order to best serve the hundreds of thousands of patients affected annually by this condition, the overall safety, efficacy and cost-effectiveness of biologic prosthetics as compared to permanent, synthetic prosthetics must be subjected to prospective, randomized clinical study. The specific hypothesis driving the research proposal is that the use of a permanent, synthetic prosthetic for the one-stage repair of complex ventral hernias will result in superior outcomes compared to use of a biologic prosthetic.