Aim: Emergency exploratory laparotomy is a high-risk procedure, but most studies are based on small sample sizes, and no nationwide studies have reported the number of patients and the mortality risk. This descriptive study reports the prevalence, incidence and 30- and 365-day mortality of all patients undergoing emergency exploratory laparotomies in Denmark from 2003 to 2014. Methods: The study population is based on the Danish National Patient Register, which includes all patient contacts with Danish hospitals, including patients undergoing emergency surgery. All patients were followed in registers on mortality. Rates and proportions were estimated using Poisson and logistic regression models. Results: The number of prevalent patients was 15,330 through the period (2003–2014) of whom 13,795 were incident patients. Prevalence increased with age and peaked at 1% for the 80- to 84-year-old age group. The overall incidence was 27 per 100,000 person-years, which strongly increased with age (87 per 100,000 person-years among men and 85 per 100,000 person-years among women). The 30-day mortality was 16.5% and the 365-day mortality was 23.1%. Both increased strongly with age and did not improve over the study period. Both 30- and 365-day mortality were higher among unmarried patients compared to married patients. Conclusions: Emergency exploratory laparotomies are common high-risk procedures especially for the elderly population. These results can be used to focus on better postoperative care to reduce the mortality.