It is our purpose to clarify the relationship between serum lipid levels and the incidence of ischemic heart disease. 135 outpatients including 91 males and 54 females were divided into three groups, that were the first group below 40 years old in males or 43 years old in females, the second group from 40 years old in males or 43 years old in females to 65 years old, and the third group over 65 years old. These cases suffered from hypertension in 41.8% in males or 44.4% in females, diabetes mellitus in 7.7% or 16.7% respectively, and several kinds of diseases such as neurocirculatory asthenia, angina pectoris, hyperlipidemia and cerebral arteriosclerosis.No lipid-lowering drug was prescribed in these cases, while antihypertensive drugs were used only in 5.2% of these cases.ST depression in this article was more than 0.5mm of ST depression such as ST horizontal or sagging depressions. In the cases with ST depression, there were often found high systolic or diastolic blood pressure levels in second groups or male third group, left ventricular hypertrophy by voltage criteria in second or third groups, and high relative body weight ratio in male second group or female third group.The following findings were also observed in the cases with ST depression. Serum HDL-cholesterol tended to decrease in male third group, while triglyceride to increase. Cholesterol/HDL-choesterol was higher and cholesterol/triglyceride was lower in male third group. VLDL tended to increase in third groups, and LDL in males. LDL/VLDL was lower in males and tended to be lower in females, suggesting the disturbed metabolism between VLDL and LDL.Uric acid tended to increase in both sexes, and fibrinogen or free fatty acids in the cases except female third group.