There has been intense interest in the role of the n-3 long-chain polyunsaturated fatty acid (LCPUFA) docosahexaenoic acid (DHA, 22:6n-3), in growth and development of infants. In 2009, there are at least twelve published randomized controlled trials (RCT) assessing the effects of LCPUFA supplementation of infant formula for preterm infants and seventeen RCTs involving formula-fed term infants. In addition, at least five RCTs have investigated the effect of DHA supplementation during pregnancy and/or lactation on infant and early child development. Collectively, the published literature has demonstrated no harm of dietary LCPUFA for infants regardless of whether they are born preterm or at term. However, developmental benefit is more consistently observed in infants born preterm. This may be explained by the fact that DHA accretion to neural tissues peaks during the fetal brain growth spurt in the last trimester of pregnancy. Infants born preterm are denied the full gestation period to accumulate DHA and are at risk of incomplete DHA accumulation. New research is focused on the timing and dose of DHA supplementation needed to optimize developmental outcomes.