Characteristics of water retentivity and seasonal changes in available water were investigated in three upland soils in Northeast Thailand in order to obtain information for field crop cultivation under rainfed conditions. In general, the water retentivity at pF 1.8 to 2.7 was the highest at the soil surface within the profile, due to the contribution of soil organic matter. Based on the data on the changes of available water (pF 1.8-4.2) during a period of about two years, the amount of available water was found to be sufficient for upland farming in the rainy season. However, the content started to decrease from the beginning of the dry season. The available water content gradually decreased from the soil surface to the zone at a depth of less than 100 cm in the dry season, while it was not significantly affected in the zone at a depth of more than 100 cm. Therefore even in the dry season, a relatively large amount of available water was present in the deep layers, especially in the Quartzipsamment soil. Accordingly, cropping season, kinds of crops and soils be must judiciously selected in future farming plans.