The objective of this study was to evaluate the chemical composition of the seed, pulp, flesh, and peel of spaghetti squash (SS) in order to assess its nutritional and health benefits. Results showed that several of the following nutrients were found in significant amounts in different parts of SS: fat, protein, amino acids like cystine, vitamins, and mineral elements like selenium in the seeds; vitamin C and trigonelline in the flesh; and calcium and tartronic acid in the peel. Analysis of the index of nutritional quality for Ca, P, K, Na, Fe, Zn, VA, VB1, VB2, VC, non-fiber carbohydrate, protein, fat, and dietary fiber revealed that the SS seed, pulp, flesh, and peel are excellent sources of protein, dietary fiber, vitamin C, and minerals. The seed was a source of several nutritional components that could improve the growth and development in children, the flesh contained components that help to maintain blood glucose stability and assist hypoglycemic function, and the peel contributes calcium and weight-loss products to help increase bone density and reduce weigh respectively. These results suggest that spaghetti squash makes a source of valuable nutraceuticals.