Investigations have been carried out to determine the influence of soil moisture, i.e. pF:0, 1.5, 2.2 and 2.7, after young panicle formation stage on the protein, fat and ash contents in lowland brown rice of two varieties. The results indicated that all the components were influenced by the soil moisture conditions. According as the soil moisture decreased, the protein content increased and the ash content decreased. On the other hand, the fat content increased slightly after decreasing from pF 0 to 1.5. With respect to the effects of soil moisture upon the components, the largest was on the ash and the second was on the protein.