The high-resolution satellite sensor ASTER should be a useful tool for the monitoring of water quality in Lake Shinji and Lake Nakaumi. However, the method for extracting water quality information from ASTER data has not been established. This study presents a model for estimating turbidity and chlorophyll-a concentration(Chl-a)in these lakes using ASTER/in-site data sets. The validity of the model was checked using data from water quality surveys conducted simultaneously with satellite observation in these lakes. Consequently, the feasibility of quantifying turbidity and Chl-a with sufficient accuracy was shown using data of bands 1, 2, and 3 of ASTER. However, an accurate result could not be obtained without field validation of the model.