A study on the distribution and community structure of benthic molluscan shells of the northern coastal area in Cheju Island was carried out from July 1989 to June 1990. The benthic molluscan shells collected and identified were composed of 3 classes, 9 orders, 29 familes and 81 species. The first dominant species of the wpper intertidal zone of the northern coastal area in Cheju Island was Nodilittorina exigua and second dominant species were Heminerita japonica, Monodenta neritoides, Monodota neritoides, Littorina brevicula, those of middle intertidal zone were Lunella coronata coreensis, Monodonta neritoides and Omphalius rusticus. H. japonica, M. neritoides, O. rusticus, L. coronata coreensis and Niotha livescens were dominant in the lower intertidal zone, and Astralium haematragum was dominant in the infralittoral zone of within 60 feet sea water depth. The benthic molluscan standing biomass of intertidal and infralittoral zones were 145.71-705.55 gr/ /m sup 2 / and 84.57-1645.67 gr/m sup 2/ respectively, But thao among area and zones were apparently differences.