In many geographical regions, both in developing and in developed countries, the number of health workers is insufficient to achieve population health goals. Financial incentives for return of service are intended to alleviate health worker shortages: A (future) health worker enters into a contract to work for a number of years in an underserved area in exchange for a financial pay-off. The authors of this paper carried out a systematic literature search of PubMed for studies evaluating outcomes of financial-incentive programs published between 1957 and 2007.