A vascular pathogenesis of hepatic focal nodular hyperplasia (FNH) has been suggested; this study was aimed to evaluate in families with hereditary hemorrhagic telangiectasia (HHT) the prevalence of FNH, relating it to presence and stage of hepatic vascular malformations (VMs). Fifty-two HHT families underwent a screening program including abdominal Doppler sonography (US) searching for hepatic VMs; we classified them as minimal, moderate and severe, depending on the number and degree of abnormalities found by Doppler US. Presence of focal liver lesions was recorded. Diagnosis of FNH was made if at least two examinations, whether color Doppler US, liver scintigraphy, dynamic computed tomography (CT) or magnetic resonance (MR), showed suggestive findings. FNH was found in five out of 274 subjects (1.8%). All five were affected by HHT. Thus, percentage related to the group of affected patients increased to 2.9; 4/5 presented severe liver VMs. Female-to-male ratio was 4:1. FNH was single in three cases; tumor size ranged between 20 and 90 mm. During follow-up, no lesion showed a reduction in size, three showed an increase. Prevalence of FNH in patients with HHT is far greater than that reported in the general population; Doppler US role in its diagnosis and follow-up is highlighted.