Introduction: Emergency laparotomy is associated with significant morbidity and mortality. This study compared emergency laparotomy outcomes in a traditional service to those after the introduction of an Acute Surgical Unit (ASU). Methods: A retrospective cohort study was performed by reviewing the medical records of all individuals that had an emergency laparotomy in twelve-month periods before and after the introduction of an ASU. Outcomes included time to surgical review, operation duration, length of stay, complications and mortality. Morbidity and mortality were compared to that predicted by P-Possum scores. Results: In the pre-ASU group there were 58 participants (26 males, 32 females) with a median age of 60 years (range 15e87) and median P-Possum predicted morbidity and mortality of 68% (18e98%) and 6% (1e66%) respectively. In the post-ASU group there were 109 participants (58 males, 53 females) with a median age of 63 years (range 11e100), and median P-Possum predicted morbidity and mortality of 82% (18e100%) and 12% (1e99%). Operating time decreased post-ASU (median 1 hr 31 min pre vs 1 hr 15 min post p ¼ 0.030) and there was a reduction in the incidence of post-operative fistula formation (5% vs 0% p ¼ 0.017). There were no other significant differences in morbidity or mortality. Conclusions: The post-ASU cohort had shorter operative duration and reduced incidence of complicating fistulas but no other significant difference in outcomes. Further studies may define the impact of an ASU on clinical decision making, service delivery, morbidity and mortality in patients that undergo emergency laparotomy.