Purpose In 2018, the Act to Improve Training Conditions and the Status of Medical Residents (AITR) was fully implemented in South Korea. This study aimed to investigate the effects of AITR implementation on the clinical outcomes of patients who underwent emergency abdominal surgery. Materials and Methods A total of 2571 patients who underwent emergency abdominal surgery after visiting the emergency room (ER) between 2015 and 2019 was included. Electronic medical records were retrospectively reviewed. In addition, a comparative analysis was performed for patient groups treated before and after AITR implementation. Results The median patient age was 48.0 years, and 49.2% of them were male. Appendicitis was the most common diagnosis (82.6%), followed by major abdominal emergencies (9.9%) and cholecystitis (7.5%). The median time from arrival to surgery was 439 min, and 52 (2.0%) patients died. A comparison of patients who underwent surgery before (pre-AITR; 1453, 56.5%) and after (post-AITR; 1118, 43.5%) AITR implementation revealed a significant difference in age, number of residents on a 24-h shift, and diagnosis. The time from ER arrival to surgery was not significantly longer after AITR implementation than before AITR implementation (434 min vs. 443 min, p =0.230). AITR was not a significant risk factor for mortality ( p =0.225). Conclusion The time from ER arrival to emergency surgery did not increase significantly after AITR implementation, and there was no difference in the patients’ clinical outcomes.