Abstract: Imprinted genes are epigenetic modifications that make a pair of alleles express only paternal or maternal genes. Most of the imprinted genes exist in the placenta and are very important for placental and embryonic development. Imprinted genes are an indispensable part of the study of the pathogenesis of being small for gestational age. However, relevant research is controversial and has not yet reached a common conclusion. In this paper, recent studies on the relation ofimprinted genes and being small for gestational age are reviewed.