For the chemical assessment of soybean sprouts as a protein food, the changes of amino acid compositions were investigated in soybean as well as both in cotyledon and axis at various growing stages. The total amino acid content per soybean sprout was not changed until 2 days, and thereafter decreased. In cotyledon it is decreased but increased in axis. The ratio of essential amino acid to total amino acids decreased rapidly after 4 days, especially in axis. Aspartic acid increased considerably while glutamic acid decreased. The assessment of soybean sprout with chemical score, A/E and A/T, methods showed that the values were low and that there was no consistency among two methods for sprout products. The limiting amino acid was methionine. Both chemical scores by FAO reference protein and requirement pattern showed similar decreasing order of 2 day-sprout$gt; soybean$gt;4 day-sprout$gt;8 day-sprout$gt;6 day-sprout, while both essential amino acid index and requirement index showed 2 day-sprout$gt;soybeans$gt;4 day-sprout$gt; 6 day-sprout$gt;8 day-sprout.