The growth and amino acid contents of the cyanobacterium, Spirulina platensis strain NIES 46, were investigated using ammonium, nitrate, nitrite, or urea as the sole nitrogen source in a batch culture. Chlorophyll a concentration was highest at 2,096$mu extrm{g}$/L in the nitrate group after 10days of cultivation, while the dry weight of S. platensis was highest at 4.5g/L in the ammonium group after 30days of cultivation. The total amino acid content was highest at 174mg/g dry weight of S. platensis in the urea group at the end of the cultivation period, yet the amino acid patterns for S. platensis were similar for all the experimental groups. Therefore, it seemed that the growth and amino acid composition of S. platensis varied depending on the type of nitrogen sources, while the amino acid patterns were not changed. Also, the most efficient harvesting time for S. platensis seemed to be approximately 10 days after cultivation.