Spontaneous sac size regression of a giant abdominal aortic aneurysm (AAA) is a rare event that has not been previously described. We report a case of an 89-year-old woman with a known 9-cm AAA, which was diagnosed in 2003. The patient had refused any kind of treatment at that time. Recent imaging studies obtained 7 years later revealed an AAA of 4 cm diameter. This is the first recorded case of significant spontaneous AAA sac shrinkage.