Seasonal variations of contents of moisture, protein, fat, ash and glycogen, and compositions of fatty acids, and amino acids were investigated in the meat of the surf clam, Spisula sachalinensis. The glycogen content was highest in July (7.3%) and lowest in January (2.8%) The major amino acids were glycine, taurine and alanine. Taurine was detected at the level of 1100 to 2500mg/100 g throughout the year, and was largest in February. A reverse correlation was observed between free amino acid content and glycogen level. The content of moisture, protein, fat, and ash, the lipid class compositons and fatty acid compositions were almost unchanged throughout the year.