Comparison of the distribution and utilization of free amino acids in buckwheat is required of understanding the amino acid metabolism. The buckwheat sprouts contained the most abundant amino acid Val (40%) followed by Tyr (28%) in common buckwheat (CB), whereas Val was the most predominant amino acid in tatary buckwheat (TB), accounting for 62%. The buckwheat stem and root contained commonly Gln (40~42% in stem; 30~37% in root). Thus, soluble amino nitrogen source is used for Gln in buckwheat. The main difference of amino acid distribution in three tissues between CB and TB was Tyr in sprouts. Low level of Tyr in TB is presumably resulted from the conversion to other phenolic metabolites. The content of essential free amino acids in TB sprout was 53% higher than that in CB. Thus, the TB sprouts are benefit to the human nutrition. The basic study of amino acids gives a clear evidence for different interconversion and metabolism of amino acids in two buckwheat species.