The authors investigated the relationship between the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism and the blood flow characteristics of common carotid (CCA) and brachial arteries (BA) by color Doppler ultrasound (CDUS) in patients with acute anterior myocardial infarction (AAMI). Sixty four patients (11 women and 53 men), aged 25 to 77 years, with AAMI were studied. The ACE genotypes were established. Peak-systolic (PSV) and end-diastolic velocity (EDV) of right and left CCA, PSV of right BA, and intimal-medial thickness (IMT) of both CCAs were measured by CDUS. All results were evaluated statistically. The ACE genotypes were distributed as follows: 43.8% DD, 43.8% ID, and 12.5% II. PSVs of BA and both CCAs were lower in patients with DD and ID than with II (p<0.05). EDVs of both CCAs were also lower in the same groups, but statistically not significant (p>0.05). IMTs of both CCAs did not differ among patients with various ACE genotypes (p>0.05). These results suggest that ACE I/D polymorphism influences Doppler blood flow parameters of both BA and CCA, but does not affect IMT of CCA.