To evaluate Lp(a) as a genetic risk for atherosclerosis, we compared the prevalence of atherosclerotic vascular disease (AVD) in a family members of 10 probans (1 male and 9 females, an average age of 70 ± 11) having high Lp(a) (≥ 100 mg/dl) with those of 10 control probands (1 male and 9 females, average age of 71 ± 10) of low Lp(a) (< 10 mg/dl). Ten control probands were chosen to match number, age, sex and disease with those of high Lp(a) probands (2 myocardial infarction, 2 cerebral infarction, 3 hyperlipidemias, 2 hypertension and 1 pulmonary emphysema). Lp(a) averaged 126 ± 29 mg/dl and 7 ± 2 mg/dl, respectively. The number of adult members in the total families was 137 and 129, and their Lp(a) averaged 31 ± 25 mg/dl and 12 ± 9 mg/dl, respectively. Among them, we found 17 subjects had AVD in high Lp(a) group, while 7 had vascular episodes in low Lp(a) group. Thus, prevalence of AVD was significantly high in pedigrees compared with low Lp(a) group; 12% vs. 5%, (p < 0.05).