The chemical components, lipid class, and fatty acid composition of muscle from male and female common squid, Todarodes pacificus, were examined to evaluate the potential utilization of muscle from fin, head, arms, and tentacles, which consumers usually like less than the mantle. The mantle was found to constitute 47-49% of the total muscle and the proportion was slightly higher in females than in males. For the remaining 51-53% of the muscle, the only gender difference was that the arms of males contained approximately 3% more muscle than those of females (P<0.05). The protein content was higher in the mantle, arms, and tentacles than in the fin and head in both males and females (P<0.05), and was slightly higher in males (15.7-20.7%) than in females (15.1-19.2%). By contrast, the lipid content was slightly higher in females (1.82-2.54%) than in males (1.01-2.37%), and the fins in both males and females contained the most lipids (2.37-2.54%) of all muscle. The prominent lipid classes in the muscles were free sterol (males 81.5-91.9% vs. females 84.9-91.8% for the non-polar lipid content), phosphatidylcholine (PC, males 59.3-62.4% vs. females 49.2-57.8% for the phospholipid content) and phosphatidylethanolamine (PE, males 22.0-28.8% vs. females 25.6-33.8% for the phospholipid content). The percentage of PC was approximately 5-10% higher in males (P<0.05), especially in the fin, while that of PE was approximately 3-5% higher in female (P<0.05), especially in the head. All of the squid muscle contained 52.1-54.9% of n-3 polyunsaturated fatty acids (PUFA), such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Males contained slightly more DHA, whereas female contained more EPA. The total percentage of n-3 PUFA differed little among muscles within the same gender.