In order to recycle dredged soil, our research group developed interlocking blocks from dredged soil. Dredged soil interlocking blocks (350 mm in width, 350 mm in depth and 100 mm-150 mm in height) were made from soft clay dredged at the Kanmon Waterway. They were produced with the constant pressure 5 MPa and cement content of 15 %, 20 % and 25 % per the dry weight of clay. On the other hand, Katagiri3) developed dredged and dewatered soil. The unconfined compression test was carried out to investigate material characteristics of dredged soil interlocking blocks and dredged and dewatered soil. The following conclusions are obtained: (1) There was relationship between unconfined compressive strength and dry density about dredged soil interlocking block, but there wasn't much relationship about dredged and dewatered soil. (2) There was relationship between unconfined compressive strength and water content about dredged soil interlocking block, but there was no relationship about dredged and dewatered soil. (3) Inclination of relationship between unconfined compressive strength and water-cement ratio was almost the same about dredged soil interlocking block cement content of 20 % and dredged and dewatered soil cement content of 15 % and 20 %.