Aims: Socio-economic disparities in health and access to care are well documented, but socio-economic disparities in surgical care and outcomes have received less attention. The aim of the study was to determine if there are socio-economic disparities in the risk of undergoing emergency laparotomy and postoperative mortality in a universal health-care system with free and equal access to care. Methods: This was a nationwide case-control study including patients undergoing non-malignant emergency laparotomy involving resection, ostomy or open drainage between 2003 and 2014 and population references matched 1:1 on age and sex. Socio-economic disparities in one-year postoperative mortality were explored through a cohort study including all patients. Exposure measures were register-based household disposable income, educational level and employment status. Analyses were adjusted by age, sex, country of origin, marital status and co-morbidity. Results: A total of 11,962 cases and 11,962 population references were included. The highest odds ratios (OR) for undergoing surgery were found among those with the lowest income (OR=1.51; 95% confidence interval (CI) 1.39-1.63), those with elementary school education (OR=1.33; 95% CI 1.22-1.46) and those on early-retirement pension (OR=3.49; 95% CI 3.07-3.98). One-year postoperative mortality was highest among those with lowest income (hazard ratio (HR)=1.51; 95% CI 1.35-1.69), those with elementary school education (HR=1.39; 95% CI 1.22-1.59) and those on early-retirement pension (HR=2.12; 95% CI 1.73-2.61). Conclusions: Socio-economic disparities in health exist in relation to non-malignant emergency laparotomies and still exist after adjustment for confounders, including co-morbidity, indicating that mechanisms other than differences in disease burden are involved. There is a substantial need for exploration of mechanisms and preventive measures.