Background: The management of patients with asymptomatic Kommerell diverticulum (KD) with aberrant left subclavian artery (ALSA) has been controversial due to a lack of knowledge about the natural history. We aimed to explore the size and growth pattern of KD and its relationship with age and sex. Methods: This was a single-center observational retrospective study focused on KD with ALSA patients incidentally diagnosed via computed tomography (CT) scans. Measurements on KD in all dimensions, diameters of ascending and descending aorta (AAo and DAo), and distal left subclavian artery (dLSA) were performed. Clinical and demographic features were collected using the medical records system. Followup information was also collected. Correlations between age and KD measurements were analyzed across different genders. A comparison of the demographic features between potential surgical candidates, according to the present criteria, and other cases was performed. Results: A total of 67 KD patients (mean age 53.8 +/- 14.5 years) were included. There were 42 males (62.7%) and 25 females (37.3%). The average sizes of KDs, AAo, DAo, and dLSA were larger in males. A positive correlation was found between KD size and age in females (P<0.05), which was insignificant in males. There were no correlations between age and KD measurements indexed to AAo, DAo, or dLSA in both males and females (P>0.05). The median follow-up period was 50 months (ranging from 5 to 129 months). Most patients (95.5%) had no symptoms or deadly vascular events related to KD during follow-up, with only three male patients having died from pulmonary infection or heart failure. Potential surgical candidates were significantly older than non-potential surgical candidates (P=0.004). Conclusions: Patients incidentally diagnosed with asymptomatic KD with ALSA tend to have a benign natural history, and related major vascular events are rare in the short term. In cases with large KD and severe atherosclerosis, regular imaging and clinical follow-up would be suggested.