To assess the relationship between angiotensin-converting enzyme (ACE) gene polymorphism and myocardial infarction in Koreans, we recruited 112 healthy, unrelated subjects (mean age 53.4 years) and 104 myocardial infarction survivors (mean age 54.2 years) of both sexes. An insertion/deletion (I/D) polymorphism of the ACE gene was typed by polymerase chain reaction. The I allelic frequency of ACE gene in Korean subjects was irrelavant to myocardial infarction (patients, 65%; control subjects 66%), as was true with the D allele. When compared with other populations, the frequency of D allele in Koreans (0.34) was lower than that in Caucasians, and was close to that of other Oriental populations. The data suggest that the ACE gene polymorphism is not an independent genetic risk factor for myocardial infarction in Koreans.