Familial hypercholesterolemia (FH) is a relatively common autosomal monogenic disease with dominant inheritance and threefold to fourfold increase in relative risk of cardiovascular death in untreated patients. For a "definitive" clinical diagnosis of FH the Simon Broome Register proposes the presence of tendon xanthomas as a key feature. However, detection of tendon xanthomas by physical examination is subjective and difficult to use for follow-up purposes. Several instrumental methods have been reported to be more sensitive than physical examination for the evaluation of xanthomas. The present case illustrates the usefulness of computed tomography (CT) to detect xanthomas in the Achilles tendons (XAT) and their regression in response to hypolipidemic drug treatment in a heterozygous FH patient. As XAT are atherosclerotic plaque-like depositions of lipids it is likely that their progression or regression follows the behavior of vascular atherosclerotic lesions.