Our team is establishing a Payment for Ecosystem Services (PES) market, whereby landowners (primarily engaged in cattle and hay production) implement best management practices that result in provision of ecosystem services (wildlife habitat and water resources/ riparian function), in exchange for payment from voluntary buyers (for example, energy companies in need of off-site mitigation credits). The PES market is called the Upper Green River Conservation Exchange and is currently conducting pilot transactions. How do we structure the market to ensure voluntary landowner (i.e., seller) participation? Issues include how to deal with grazing allotments on public lands, how to structure the risk of non-attainment of ecological target outcomes; and which ecosystem services/management practices and contract terms are of interest on a working landscape in this region. We present the results of a survey designed to inform analyses of factors affecting landowners’ stated willingness to participate in a PES market; and program design preferences: what ecosystem services (wildlife habitat and water resources/riparian function) and program features (management practice, contract length, payment level) are of interest to landowners (choice experiment analysis).