This laboratory study was performed to produce basic data for the estimation of water requirements for desalinization, through analyzing changes of the electrical conductivity and the exchangeable sodium percentage during the desalinization of reclaimed tidelands. Desalinization experiments were carried out by two water management practices, namely, the leaching method by subsurface drainage and the rinsing method by surface drainage, using samples of silt loam soil and silty clay loam soil collected in reclaimed tidelands. The results obtained from this study were summarized as follows : 1. The sample soils used in this study were saline-sodic soils with the high electrical conductivity and the high exchangeable sodium percentage. 2. Changes of the electrical conductivity and the exchangeable sodium percentage with water requirements for desalinization showed a similar tendency in the desalinization experiment by the same water management practice. 3. The regression equation between the relative electrical conductivity(EC/EC) and water requirements for desalinization(Dw/Ds) could be described by Dw/Ds=0. 029×(EC/EC。) ^-0.982 (Leaching method), Dw/Ds=3. 678×0. 030^(EC/EC) (Rinsing method). 4. The regression equation between the relative exchangeable sodium percentage (ESP/ESP) and water requirements for desalinization (Dw/Ds) could be expressed in Dw/Ds = 0.039×(ESP/ESP。) ^{- 1. 134} (Leaching method), Dw/Ds=7. 197×0. 024^(ESP/ESP) (Rinsing method). 5. It was estimated that water requirements for the adequate desalinization would be Dw/Ds=0.3 (Leaching method) and Dw/Ds=3.0 (Rinsing method).