This study was carried out in 14,443 subjects(8,706 men, 5,737 women, mean age $41.8{pm}9.16$) who visited the health promotion center of one university hospital. Serum $T_3$, $T_4$ and TSH concentrations were measured with CIA using commercial kits on ADVIA Centaur Assay and Serum total cholesterol, triglyceride, and HDL-cholesterol were measured by auto-analyzer Hitach 7600 in enzyme method. 1. The prevalence of subclinical hypothyroidism was 12.6/1,000 population(men 6.0/1,000, women 22.7/1,000) and as high as about 4 times in women than in men. 2. In subclinical hypothyroidism, the values of total cholesterol and LDL-cholesterol were significantly high by 5.5 mg/dL, 4.6 mg/dL compared with normal group(p<0.05). 3. In all the tested hypercholesterolemia and hyperLDL-cholesterolemia, were correlated with TSH. There is higher correlation in women group than men group. These results indicate that the subclinical hypothyroidism and dyslipemia significantly correlated. Especially, it is very important to find that the hypercholesterolemia and hyperLDL-cholesterolemia are the high risk factors of atherosclerosis. Therefore, it is essential for the group of subclinical hypothyroidism to take the cholesterol, LDL-cholesterol and serum lipid test as well as thyroid function test.