Fish and marine invertebrates are an important part of our diet as they contribute to the intake of health‐pro omega‐3 fatty acids and possibly to prevention and treatment of coronary heart diseases. The crude protein contents of seafoods generally vary between 11.0% and 28.4% (usually about 19.0%), and the content of lipid in muscle tissue is inversely related to its moisture content. The contribution of non‐protein nitrogenous compounds to the total crude protein content of seafoods depends on the species of raw material and range from 10% to 40%. While the amount of fat‐soluble vitamins in seafoods is often higher than those in land animals and depends, to a large extent, on the species, the content of water‐soluble vitamins in seafoods is less dependent upon the species. The content of minerals in seafoods is slightly higher than those in terrestrial animals. The flavor of seafoods depends on the species, the fat content, and the presence as well as the type of nonprotein nitrogenous compounds.