The quantities of 17 amino acids (tryptophan not included) were determined in the protein fractions of mature grains of two spring wheat cultivars with different baking qualities. They were grown under different nitrogen fertilizer levels during two seasons in the field and one in the greenhouse. The total amount of amino acids increased with increased nitrogen fertilization in five cases out of six. This was mainly attributed to the increase in the gliadins and in some cases the glutenins as well. In relative figures, there were only slight differences in the amino acid composition of the individual protein fractions at different levels of nitrogen input. Similarly, the relative total amounts of the different amino acids were not affected by the different nitrogen fertilizer levels used. However, one of the two cultivars had a higher percentage of glutamate- and proline-rich proteins than the other.