The Environmental Protection Agency has used existing studies to estimate the benefits of environmental improvements associated with several regulatory proposals. The problems encountered in using existing studies to measure the benefits of water quality improvements are investigated in this paper. We propose criteria for selecting transfer studies and present a case study of a transfer. Our research indicates that although benefit transfer may offer promise, the fact that existing studies were not designed for transfer places severe limitations on the current effectiveness of transfer. Suggestions for future research are presented to address these limitations.