1. Levels of total fatty acid and carbohydrate were followed in digestive glands and gonads of the starfish, Echinaster, collected at monthly and bimonthly intervals throughout its annual cycle of growth and reproduction. 2. Fatty acid almost always occurs in the tissues at over ten times the concentration of carbohydrate and exhibits a more clearly defined systematic variation in the cycle. 3. The total content of fatty acid and carbohydrate in the bodies of both sexes increases gradually from summer until a month preceding spawning, the following May. Approximately one-half the accumulated reserves are lost in the final reproductive effort. 4. Females tend to have higher fatty acid contents than males because of low levels in the testes. The ovaries begin accumulation of fatty acids in the fall, whereas testes build up only a small amount in the late winter. 5. The annual variation in fatty acid content of the digestive glands is due to fluctuations of both the tissue concentration and the size of the organs. Concentration increases in early fall and then declines as the organs enlarge. It is suggested that digestive gland size is only indirectly related to nutritional state and may be under hormonal control.