In order to study the coronary artery structure in relation to early atherosclerotic lesions of young adults residing in a fishing region, coronary arteries from 80 autopsies of people aged 15 to 39 years who died from accidents were collected and studied by pathohistological, immunohistochemical and morphometric methods. The results showed an 18.67% prevalence of Sudanophilic lesions in the right, coronary artery, the thickness of the intima of the left anterior descending branch increased with increasing age in males, but no significant difference was observed in females, the density of the coronary artery cell nuclei decreased with increasing age. The prevalence of fatty streaks and stenosis of left anterior descending branch was 25.0% and 5.0% respectively, and that of the left circumflex branch was 7.5% and 3.9% respectively. The amount of chondroinn sulfate proteoglycan in the left anterior descending branch was 23.3 +/- 8.8% in intima and 12.0 +/- 4.0% in the media. The above findings suggest that the custom of eating large amounts of sea food may have a beneficial effect on lipid deposit, smooth muscle cell proliferation, thickness of intima and percentage of proteoglycan. Thus it is one of the important factors for the low incidence of coronary heart disease in this fishing region.