Seasonal differences of contents of free amino acids and sugars of the lower-parts of rice stems whose leaf blades were cut off at six different stages of growth of rice plants were studied by paper chromatography. Amino acids found always in both of treated and non-treated rice culms were as follows: aspartic acid, glutamic acid, glycine (or asparagine), alanine, threonine (or glutamine), α-amino butylic acid, valine, leucine, serine, tyrosine and cystic acid. No qualitative effects on the members of amino acids were found by the reduction of the leaf blades. Sugars found always in the above mentioned culms were sucrose, glucose and fructose. It seems likely that there exist some correlations between the decrease of sucrose contents of the stem bases of rice plants and the increase of severity of stem rot of rice plants whose leaf blades were cut off at different stages of the plant growth.