Large-scale population studies of the incidence of and mortality from abdominal aortic aneurysm (AAA) are needed to develop healthcare policies and priorities. The aim of this study was to estimate the incidence of AAA and the all-cause mortality from it among Koreans aged ≥50 years from 2009 to 2018 using data from the Korean National Health Insurance System Database. The crude and standardized incidence and all-cause mortality of the disease among patients with unruptured AAA were calculated. A total of 73,933 AAA patients were identified. The overall incidence of AAA in adults ≥50 years during the study period was 37.5 per 100,000 population (49.7 per 100,000 in men and 26.8 per 100,000 in women), with an increase from 32.33 per 100,000 persons in 2009 to 46.85 per 100,000 in 2018. The crude all-cause mortality rate of patients with untreated AAA was 21.26/100 person-years in 2009 and 8.87/100 person-years in 2018, with decreasing trends observed both in men and women. This nationwide study showed that the incidence of AAA in Koreans aged ≥50 years in 2018 was 63.40 per 100,000 in men and 32.07 per 100,000 in women. The overall rates were 0.06% and 0.03%, respectively, with an increasing trend. Mortality has decreased in both treated and untreated patients. The observed increase in incidence suggests a rising burden of AAA in the Korean population, particularly among men. The decreasing mortality rates may indicate improvements in the management and treatment of AAA over the study period.