Background: Emergency abdominal surgery carries a 15% to 20% short-term mortality rate. Postoperative medical complications are strongly associated with increased mortality. Recent research suggests that timely recognition and effective management of complications may reduce mortality. The aim of the present trial is to evaluate the effect of postoperative intermediate care following emergency major abdominal surgery in high-risk patients.Methods and design: The InCare trial is a randomised, parallel-group, non-blinded clinical trial with 1:1 allocation. Patients undergoing emergency laparotomy or laparoscopic surgery with a perioperative Acute Physiology and Chronic Health Evaluation II score of 10 or above, who are ready to be transferred to the surgical ward within 24 h of surgery are allocated to either intermediate care for 48 h, or surgical ward care. The primary outcome measure is all-cause 30-day mortality. We aim to enrol 400 patients in seven Danish hospitals. The sample size allows us to detect or refute a 34% relative risk reduction of mortality with 80% power.Discussion: This trial evaluates the benefits and possible harm of intermediate care. The results may potentially influence the survival of many high-risk surgical patients. As a pioneer trial in the area, it will provide important data on the feasibility of future large-scale randomised clinical trials evaluating different levels of postoperative care.Trial registration: Clinicaltrials.gov identifier: NCT01209663.