Community structure of ground beetles in Seokmun- and Siwha-reclaimed lands was investigated with pitfall traps from 21 May to 1 November, 2010. Survey areas were divided by the status of reclamation, vegetation, and flooding frequency. Status of the Seokmun-reclaimed land in Chungcheongnam-do is the progress of conversion to rice paddy after completion, and then dominant plant is Secale cereals. For the Siwha reclaimed land in Gyeonggi-do, reclamation is ongoing, and thus Imperata cylindrica and Calamagrostis pigeios are dominant plants. Flooding was more frequent in Seokmun than in Siwha as 4 times and none, respectively. A total of 3,352 epigeic insects of 9 orders and 22,981 epigeic insects of 9 orders were collected from the Seokmun- and Siwha-reclaimed land, respectively. Collembola was the most abundant in each site. In ground beetle assemblage, 11 species belonging to 7 subfamilies Seokmun and 8 species belonging to 5 subfamilies in Siwha were identified from 183 and 101 collected ground beetles. Chlaenius pallipes (107 individuals, 58.5%) and Pheropsophus javanus (52 individuals, 28.4%) was dominant in Seokmun, while Harplus jureceki (37 individuals, 36.6%), Synuchus arcuaticollis (17 individuals, 16.8%), and Dolichus halensis halensis (17 individuals, 16.8%) was dominant in Siwha. The Shannon's index value was 1.147 and 1.671 in Seokmun and Siwha, respectively. Similarity by the Sørensen index between Seokmun and Siwha was 0.3158. In conclusion, community structure and seasonality of ground beetles were significantly different between two reclaimed lands, and this difference appears to be due to their different habitat conditions such as flooding frequency and progress of reclamation.