Fat forms an important component of diet and must constitute about 20-35% of normal diet during pregnancy. Dietary fat can be normally divided into visible fat or the invisible fat, depending on whether they can be seen or not. About 40% of the dietary fat is ingested in form of visible fat. Fats serve as a dense source of energy, with each gram of fat yielding 9 Kilocalories (Kcal) of energy. The basic unit of fat is one molecule of glycerol joined to one, two, or three fatty acids resulting in formation of monoglyceride, diglycerol and triglyceride respectively. The various fatty acids vary in their length of fatty acid chain, which can vary from two to twenty four carbon atoms. From this chapter, it becomes apparent that the LCPUFAs (long chain polyunsaturated fatty acid) status at birth (especially in preterm infants) as well as prenatally seems to have a long-term effect in reducing the development of chronic inflammatory reactions, the repercussions of which can extend into the adulthood in form of cancers, auto-immune diseases, allergic disorders, metabolic syndrome X, coronary heart disease etc. Thus it becomes essential that fetus should receive an adequate supply of LCPUFAs, through maternal supplementation prenatally. This chapter also shows that the supply of higher proportion of ω-3 fatty acids to the fetus as well as infants is important for growth, visual and neural development, and long-term health. Since the time immemorial, breast milk, which is rich in ω-3 fatty acids, has proven to be the best available source of essential fatty acids for the infant.