Abstract : Two methods of repair are currently available for an abdominal aortic aneurysm (AAA), open aneurysm surgery, and endovascular aneurysm repair (EVAR). The purpose of this article is to investigate the morbidity and mortality of all cases of open surgery versus EVAR conducted from 2011 to 2019 at Sina Medical Research and Training Hospital. This research is a retrospective cross-sectional study. The study population consisted of all abdominal aortic aneurysm patients who were treated at Sina Hospital in Tehran from September 2011 to December 2019. All patients who met the inclusion criteria participated in the study. A checklist of required data was prepared and used to extract data from patients' medical case files. Morbidity and mortality information of patients was completed via telephone contact with patients or their families. Analyses were performed using SPSS software with a 5-percent error rate. The sample consisted of 194 patients who were divided into two groups. 73 patients (37.6%) underwent open surgery and 121 patients (62.4%) underwent EVAR. Rates of blood loss and blood transfusion, length of stay in the intensive care unit (ICU), a total length of postoperative hospitalization for patients who underwent open surgery were significantly higher than for those who underwent EVAR (P-value <0.001). Patients who underwent open surgery experienced more renal and cardiac morbidities than those who underwent EVAR (P-value <0.05). Morbidities associated with grafting were significantly greater in patients undergoing EVAR than in those undergoing open surgery (P-value = 0.011). Moreover, the need for intervention for postoperative morbidities was higher in the open surgery repair (OSR) group compared with the EVAR group (P-value = 0.030). The frequency of reoperation was about 3 times higher in the EVAR group in comparison with the OSR group. The frequency of death was higher in the OSR group compared to the EVAR group, so that36.6 and 25.9 of patients in OSR and EVAR groups died, respectively, although this difference was not statistically significant (P-value = 0.123). The mortality probability of patients with a history of CVA and smoking was 3.47 and 2.66 times higher than patients with a negative history of these cases, respectively. The main morbidities of open surgery include renal and cardiac complications, longer hospitalization, and need for more amounts of blood transfusion, while main morbidities of EVAR include graft thrombosis and EVAR associated morbidities (e.g. graft and endoleak migration). However, there is no difference in mortality rates of these two methods