As part of the USAID/EGAT/NRM-funded Payments for Environmental Services (PES) Associate Award, regional reports on PES activities, with a focus primarily on watershed services, were developed for Africa, Asia, and Latin America (Ferraro, 2007; Huang and Upadhyaya, 2007; Southgate and Wunder, 2007). This brief is a synthesis of the three regional reviews of Payments for Watershed Services (PWS). Payments for Watershed Services and PES are used somewhat interchangeably, but it should be recognized that PWS is actually a subset of PES where watershed services are at least one of the environmental services being targeted. This research brief provides an overview of the following PWS/PES issues if they could be characterized for the region: Regional trends in PWS implementation. Contexts and conditions that shape PWS and PES programs across the region. PWS and PES program design elements. Regional PWS program challenges. Regional factors that influence PWS and PES programs.