Today, about 1,700,000 species of animals and plants havebeen described in the world. Nearly 1,200,000 species ofthem are animals, and three fourth (900,000 species) ofthem are insects. According to the result of the recent studyon tropical forest and other major habitats, the actualnumber of insects inhabiting on Earth is estimated to reach30 million species (Lee et al., 1994). 15,000 species ofinsects have been reported in the Korean Peninsula,including about 8,200 species in South Korea and 3,604species in North Korea. On the other hand, 30,399 specieshave been recorded in Japan located near Korea (Kwon etal., 1994). Especially, the Korean Peninsula has high insectdiversity due to its variety of nature in terms of topography,geography and hydrology characterized with a variety ofclimates for small land space, stretching north and south,rising to the east, and inclining gently towards thesouthwest. As such, a number of insect species aredistributed in our natural environment, and therefore thoseinsects play a important roles from food chain in a varietyof ecosystems as consumer, decomposer, predator orparasite, which also have influence on our human beingeither directly or indirectly.There are ten Natural Reserves in Korea including theMarado Island Natural Reserve designated on July 18 in2000, starting from the Hongdo Island Natural Reserve(Natural Monument No. 170) designated on April 7 in 1965(Table 1). Except Dokdo Island or Marado Island designatedfrom the aspect of territorial expansion in part, all otherareas were designated as the Natural Reserves for thereason of their having rare living creature required to bepreserved from the aspects of landscape and science or theirenvironment of high biodiversity. The importance of theDokdo and Marado Island Natural Reserves, however, isemerging again from such an ecological aspect that theyrecently provide resting place to rare marine living creatureliving at the coastal area, southern type species that live inthe area, or the insects that move a long distance (An,2000).Accordingly, this study is intended to compare andanalyze the characteristic of insect fauna living in the areadesignated as the Natural Reserves in Korea and therebyprovide significant fundamental data that can be used orutilized in establishing the plan of managing and preservinginsect ecosystem in the Natural Reserve.