Purpose: The aim of this study was to evaluate the incidence, risk factors, and outcome of endoleaks related to endovascular aneurysm repair (EVAR) procedure at a single center with up to 10 years’ surveillance. Materials and Methods: All patients treated with EVAR for an abdominal aorta or iliac aneurysm in a 10-year period at a single cardiovascular center in Denmark were included. Data were collected from a national database and patient journals. Follow-up computed tomography angiography and plain abdominal X-ray reports were reviewed. Results: A total of 421 patients were included. There were 125 endoleaks observed in 117 (27.8%) patients after a median 95 days (interquartile range: 90-106 days). There were 16 type I, 107 type II, 1 type III, and 1 type V endoleaks. A total of 33 (7.8%) patients had at least 1 reintervention. Patients with type II endoleaks had significantly fewer active smokers and lower plasma creatinine at baseline. They also more often had one, or both, internal iliac arteries embolized as well as an identified endoleak at the procedural completion angiogram. Non-type II endoleaks were associated with internal iliac artery embolization. There was no association between the occurrence of endoleaks and increased mortality. Conclusion: Type II endoleaks are common after EVAR, yet few lead to reintervention. Absence of smoking, low plasma creatinine, embolized iliac arteries, and endoleak on completion angiogram were associated with type II endoleaks, whereas only embolized iliac arteries were associated with non-type II endoleaks. Overall, endoleaks are not associated with increased mortality.