Today, crops are traded all over the World, and it is necessary to know the agricultural situation of the World for the purpose of the food stabilization. Australia is endowed with vast agricultural resources. In New South Wales State, rice crops are cultivated at the paddy rice fields. However, the drought persisted in recent years and it caused a serious damage to the rice growing. In this study, we estimated the areas of paddy rice fields in the study site in southern New South Wales State, Australia each year using TERRA-ASTER and Landsat-4,5 TM data acquired in the flooding season (about November) and the growing season (about February) from 2002/03 to 2009/10. The study area is approximately 26km by 13km in extent. We distinguish the paddy rice fields by presence of water on initial period of flooding and transplanting. On the rice plants growing period, we identify as vegetation. We could identify the decrease of the paddy rice fields in the study site from the results. It was found that the area of the paddy rice fields in the study site was about 5,491 ha in 2006 and it was about 716 ha in 2007. 2006 and 2007 were the years that the serious drought persisted. Furthermore, we could confirm that the rice growing in the study site was under the crop rotation.