Background Depression is associated with poorer outcomes in many disease states. However, its significance in abdominal surgery is unknown. This study investigated rates of depression in emergency abdominal surgery patients and its effects on outcomes. Methods A retrospective cohort study was conducted across two UK sites and included all adult patients undergoing emergency abdominal surgery. Primary outcome was the complication rate in depressed patients, including the incidence of post-operative delirium. Secondary outcomes included mortality, time to oral intake and analgesia. Results Two hundred and ten patients were identified. The commonest indication for surgery was appendicitis (53.3%) followed by small bowel obstruction (9.5%). There was a 17% ( n = 36) incidence of depression amongst patients, most of whom ( n = 26, 72.2%) were taking antidepressants. Depression was associated with male sex (M:F 27:9 p = 0.003), higher median BMI (28 vs. 25 p = 0.013 ) and previous surgery (47.2% vs. 28.7% p = 0.032 ). Despite a higher incidence of post-operative delirium, increased time to oral analgesia and greater 30-day readmission rates in the depression cohort, multivariate analyses showed depression was not a significant independent predictor of these (OR 2.181, 95%CI 0.310–15.344; p = 0.433, OR 0.07, 95%CI 0.499–1.408; p = 0.348 and OR 1.367, 95%CI 0.102–18.34, respectively). Complication and mortality rates between depressed and non-depressed individuals were similar. Conclusion Significant numbers of patients undergoing emergency abdominal surgery have depression, but this did not adversely affect post-operative outcomes. The study included relatively small numbers of participants undergoing procedures with straightforward recovery. Larger population studies are therefore required and should focus on investigating the association between major emergency surgeries with post-operative delirium and uncontrolled pain.