The high rates of morbidity and mortality arising from preterm birth and low birth weight impose an immense burden on the health, education and social services, and on families. This paper presents the results of a systematic review of the published and unpublished evidence regarding the long-term economic implications of preterm birth and low birth weight for various sectors of the economy and for individuals. The paper highlights the variable methodological quality of the bulk of long-term economic studies of preterm birth and low birth weight and suggests ways in which these methodological limitations can be overcome. The paper reveals that preterm birth and low birth weight can result in substantial costs to the health sector following the infant's initial discharge from hospital. It can also impose a substantial burden on special education and social services, on families and carers of the infants and on society generally. In addition to the costs identified by the literature, preterm birth and low birth weight can have other long-term consequences that require evaluation from an economic perspective.