Farmland preservation programs have been used in the United States for many years. These policies have evolved from rural/agricultural zoning ordinances to a fourth generation of policies that encompass purchase of development rights (PDR) programs. PDR programs compensate landowners or farmers for agreeing not to sell farmland for development. Farmers or landowners may continue to farm; however, minor restrictions such as wise stewardship of the land and best management practices may be imposed. This study examines the impact of PDR programs on farmland conversion in the Northeastern United States. County-level data from 1982 to 1997, are used and an econometric model is developed to correspond with periods of the Census of Agriculture; i.e., 1982 to 1987, 1987 to 1992, and 1992 to 1997. Farmland conversion is specified as a function of PDR programs and other policy variables, urban infrastructure variables, landowners' demographics variables, and housing demand variables. Results of the farmland conversion model suggest that PDR programs significantly reduced farmland conversion for the first estimation period.