BACKGROUND: A growing body of literature demonstrates that irrespective of the mechanism of injury, obesity is associated with significantly worse morbidity and mortality after trauma. Among patients requiring damage control laparotomy (DCL), clinical experience suggests that obesity affects time to definitive closure though this association has never been demonstrated quantitatively. METHODS: All patients at an academic Level I trauma center requiring a DCL between January 2002 and December 2006 (N = 148) were included. Information pertaining to demographic, injury, and clinical characteristics was abstracted from patient medical records. The risk of specific complications including pneumonia, renal failure, and sepsis was compared between normal and overweight/obese patients, as measured by body mass index (BMI). The lengths of intensive care unit (ICU) stay and mechanical ventilation as well as time to abdominal closure were also compared. RESULTS: The risk of pneumonia, sepsis, and renal failure was 2.05-times, 1.77-times, and 2.84-times higher among overweight patients compared with patients with a normal BMI. The risk of pneumonia, sepsis, and renal failure was 2.01-times, 4.24-times, and 1.85-times higher among obese patients compared with those with a normal BMI. Obese patients also had a significantly longer ICU length of stay (28.7 days vs. 15.1 days; p < 0.0001), longer hospitalization (39.3 days vs. 27.0 days; p = 0.008), and time to definitive closure (8.4 days vs. 3.9 days; p = 0.03) compared with patients with a normal BMI. CONCLUSIONS: Among patients requiring DCL, those who are overweight or obese have a prolonged time to definitive closure. These patients also experience a significantly longer ICU course and a higher risk of pneumonia. © 2009 Lippincott Williams & Wilkins, Inc.