Introduction: Lumbar disc degeneration is a common and important condition. Although many factors have been suggested in association with this problem, researchers are trying to find newer, more preventable etiologies. This study aims to investigate an association between aortic diameter and lumbar disc degeneration at L4-L5. Methods: Magnetic resonance (MR) images of 50 patients with lumbar disc degeneration at L4-L5 (case group) and 50 well-matched patients without such changes (control group) were enrolled in a retrospective study. The diameter of the abdominal aorta was measures and compared between the two groups of patients. Results: There were 25 males and 25 females in each group. The mean age of the patients in the case group was 64.43 ± 11.23 years vs. 62.12 ± 10.134 years in the control group (P = 0.60). The mean diameter of the abdominal aorta was significantly higher in the case than in the control group (20.43 ± 12.23 mm vs. 16.12 ± 8.89 mm; P = 0.04). Conclusions: Atherosclerotic changes in the abdominal aorta may be connected with degenerative changes at the L4-L5.